average, in health, being 1·020, when it contains about 380 gr. of solid
matter in the pint. According to Berzelius, the proportion is about
6-3/4%, the rest being pure water. It exhibits a decidedly acid reaction,
and is never alkaline, except during disease, or the use of large
quantities of alkaline salts of the vegetable acids. The average quantity
secreted during 24 hours may be taken at 2 pints to 3 pints; as might be
supposed, a larger quantity is passed during the summer than in the winter
months.
[Footnote 247: From 1·015 to 1·025, Beale.]
Miller gives the following as the composition of healthy urine:——
In 100
Specific gravity 1·020 parts of
solid
Water 956·80 matter.
{ { Urea 14·23 33·00
{ { Uric acid 0·37 0·86
{ Organic matters, 29·79 { Alcoholic extract 12·53 29·03
{ { Watery extract 2·50 5·80
{ { Vesical mucus 0·16 0·37
{
{ { Sodic chloride 7·22 16·73
A { { Phosphoric anhydride 2·12 4·91
{ { Sulphuric anhydride 1·70 3·94
{ Fixed salts, 13·35 { Lime 0·21 0·49
{ { Magnesia 0·21 0·28
{ { Potash 1·93 4·47
{ { Soda 0·09 0·12
{
Loss 0·03
—————— ——————
1000·00 100·00
A = Solid matters, 43·2.
The presence of bile in urine, or other like fluids, may be detected as
follows:——Put a small quantity of the suspected liquid into a test-tube,
and add to it, drop by drop, strong sulphuric acid, until it becomes warm,
taking care not to raise the temperature above 122° Fahr.; then add from 2
to 5 drops of syrup (made with 5 parts of sugar to 4 of water), and shake
the mixture. If the liquid contain bile, a violet coloration is observed.
Acetic acid may be substituted for sugar.
Another test for bile consists in pouring a little of the suspected urine
into a test tube, and adding to it a few drops of tincture of iodine, when
if bile be present the fluid becomes distinctly green. Rosenbach says that
urine containing bile, when passed through white filtering paper, imparts
a yellow or brown colour to the paper. On allowing one drop of strong
nitric acid to run down the side of the moist filter it leaves a yellow
streak, soon changing to orange, with a violet border, on the outside of
which blue and emerald-green zones may be observed. These colours remain
visible for some time.
Dark-coloured urine, owing to substances other than bile, does not produce
this play of colours.
The reagents most generally employed for detecting the presence of sugar
in urine are Trommer’s (_see_ SUGAR) and Fehling’s solutions. For the
effective application of Fehling’s test, Dr Roberts[248] advises the
following method of procedure:——Pour some of the Fehling’s solution into a
narrow test tube to the depth of 3/4 of an inch; heat until it begins to
boil; then add 2 or 3 drops of the suspected urine. If the sugar be
abundant, a thick yellow opacity or deposit of yellow suboxide are
produced (and this changes to a brick-red at once if the blue colour of
the test remains dominant). If no such reaction ensue, go on adding the
urine until a bulk nearly equal to the test employed has been poured in;
heat again to ebullition, and no change occurring, set aside without
further boiling. If no milkiness is produced as the mixture cools, the
urine may confidently be pronounced free from sugar, or, at any rate, it
contains less than 1/40th percent.
[Footnote 248: ‘Urinary and Renal Diseases,’ by Dr W. Roberts.]
If the quantity of sugar is very small, viz. from a 1/2 to 1/40th per
cent., the precipitation of the yellow or cuprous oxide does not take
place immediately, but occurs after some time as the liquid cools, and the
manner of the change is peculiar. First, the mixture loses its
transparency, and passes from a clear bluish green to a light greenish
opacity, just as if some drops of milk had fallen into the tube. This
green milky appearance is quite characteristic of sugar.
Before using the Fehling’s solution it should be always examined
previously to the addition of the urine, by being first boiled alone, when
if it remains clear it may be pronounced in fit condition. On the
contrary, should the preliminary boiling give a deposit, the solution must
be discarded, and some freshly made employed instead.
Böttger has proposed the following quantitative test for the presence of
sugar in urine:
He first adds some potash to the sample of urine, and then a small
quantity of subnitrate of bismuth, and boils the mixture. If sugar is
present, the suboxide is reduced, and metallic bismuth being liberated is
precipitated as a black powder.
Another method of applying the bismuth test is as follows:——One part of
crystallised carbonate of soda is dissolved in three parts of water, and
added to an equal quantity of the urine. A small quantity of basic nitrate
of bismuth is then added to the mixture, which is then heated to the
boiling point. A black precipitate is formed if the urine contains sugar.
Horsley’s test consists in boiling with the suspected urine a mixture of
equal parts of neutral chromate of potash and solution of potash, when, if
sugar be present, a green colour will be produced, owing to the formation
of the sesquioxide of chromium.
M. Luton’s, which is a modification of Horsley’s test, a solution of
bichromate of potash is decomposed by excess of sulphuric acid, and upon
the urine being boiled with the mixture, a splendid green colour is
imparted to it. Urea, albumin, and the urates do not interfere with this
reaction.
Vidau has observed that a mixture of equal parts of hydrochloric acid and
oil of brune (oil of sesame), either in the cold, or when slightly heated,
assumes a distinct rose colour in the presence of cane or grape sugar,
provided 0·001 gramme of sugar is present for every c.c. of mixture.
One of the best methods for the accurate and quick estimation of the
amount of sugar in urine is, perhaps, the volumetric, devised by Fehling,
who employed a standard copper solution, known as ‘Fehling’s solution,’ of
the following composition:
Sulphate of copper 90-1/2 grains.
Neutral tartrate of potash 364 ”
Solution of caustic soda, sp. gr. 1·12 4 fl. oz.
Add water to make up exactly 6 ”
Of this solution 200 grains are exactly decomposed by one grain of sugar.
The following is the mode of performing the analysis given by Dr
Roberts[249]:——Measure off 200 grains of the above standard solution in a
200-grain tube, pour this into a flask, and add about twice its volume of
water; then place over a spirit lamp to boil. While the copper solution is
being heated the urine to be analysed should be diluted with water to a
known degree. In the case of ordinary diabetic urines the best dilution is
one in ten. This is obtained by carefully filling a 6-ounce measure with
water to the depth of 4-1/2 ounces, and then adding urine so as to make up
exactly 5 ounces. The mixture will then contain exactly one tenth of urine
(when the quantity of sugar in the urine is very small, a dilution of one
in five, or even the undiluted urine may be employed). The next step is to
fill a burette (which must be graduated to grains) with the diluted urine
to 0. Then proceed to add it in successive small portions to the boiling
copper solution until the blue colour has entirely disappeared. After each
fresh addition from the burette, the mixture should be raised to the
boiling point, and then allowed to stand a few seconds, so that the
precipitated copper may subside, and the observer may see, by holding the
flask between the eye and the light, whether the mixture still retains any
blue colour.
[Footnote 249: ‘Urinary and Renal Diseases,’ by Dr W. Roberts.]
As soon as the blue colour has disappeared the analysis is complete, and
the quantity of diluted urine may be read off. The percentage of sugar in
the urine can now be readily calculated. Suppose 125 grains had been added
from the burette, this represents one tenth, or 12·5 grains of undiluted
urine, and contains exactly one grain of sugar; by dividing 12·5 into 100
the per-centage of sugar is obtained, or 100/12·5 = 8; the urine contains
8 per cent. of sugar.
Another process for the quantitative determination of sugar in urine,
called by its author, Dr Roberts, “the differential density method,” is
based upon the loss of density, experienced by diabetic urine, after all
the sugar has been removed by fermentation. Dr Roberts says repeated
examples derived from diabetic urine so treated, together with
corresponding experiments made with solutions of sugar of known strength
in normal urine, and in pure water, as well as theoretical calculation
have warranted the conclusion, _that the number of degrees of density so
lost indicates as many grains of sugar per fluid ounce_.
The method, which is extremely simple, is thus performed:——Into a 12-ounce
bottle measure 4 fluid ounces of the diabetic urine, and drop into it a
piece of fresh German yeast, about as large as a cobnut or walnut; insert
a cork in the bottle, and let the cork have a nick cut in the side, to
allow of the escape of the carbonic acid. Then fill an ordinary 4-ounce
bottle with the same sample of urine, omitting to add any yeast, and cork
it in the ordinary manner. Place both bottles in a warm situation, where
the temperature is about 80° or 90° Fahr., for twenty or twenty-four
hours; at the end of which time, the fermentation being over, the scum
will either have cleared off or subsided. The fermented urine is then
poured into a proper urine-glass, and its specific gravity ascertained.
The specific gravity of the unfermented companion portion is also taken,
and by comparing the two results the loss of density is thus arrived at.
Before the respective densities are taken it is best to remove the two
samples to a cool place, where they should remain for two or three hours,
in order that they may acquire the temperature of the surrounding air.
The two following examples may serve as illustrations of the method.
I. II.
Density before fermentation 1053 1038
Density after fermentation 1004 1013
Degrees of density lost 49 25
———— ————
Grains of sugar per fluid ounce 49 25
If it be desired to bring out the result as so much per cent., this is
accomplished by multiplying the number indicating the “density lost” by
the coefficient 0·23. Thus, in the first of the above examples, 49 ×
0·23 = 11·27; and in the second 25 × 0·23 = 5·69, which are amounts of
sugar respectively per 100 parts.[250]
[Footnote 250: Roberts.]
In taking the densities Dr Roberts advises the operator to employ a
urinometer having a long scale, since the degrees are much further apart
than in the scales of the short-stemmed instruments, and are therefore
more distinct and can be more easily read off.
The following are examples of diabetic urine:
No. 1 (Simon).
Specific gravity 1018·
Water 957·00
Solid constituents 43·00
Urea Traces.
Uric acid Traces.
Sugar 39·80
Extractive matter and }
soluble salts } 2·10
Earthy phosphates 0·52
Albumen Traces.
No. 2 (Dr Percy).
Specific gravity 1042·
Water 894·50
Solid constituents 105·50
Urea 12·16
Uric acid 0·16
Sugar 40·12
Extractive matter, and}
soluble salts } 53·06
No. 3 (Bouchardat).
Water 837·58
Solid constituents 162·42
Urea 8·27
Uric acid Not isolated.
Sugar 134·32
Extractive matters, and }
soluble salts } 20·34
Earthy phosphates 0·38
“Diabetic urine usually possesses a peculiar smell, which has been
compared with that of violets, apples, new hay, whey, horses’ urine, musk,
and sour milk. Such comparisons serve only to show how difficult it is to
give by description a correct idea of a particular odour. The colour of
diabetic urine is generally pale. Sometimes, but not usually until after
two or three days, the surface becomes coloured with a whitish film, owing
to the development of the _sugar fungus_, and the _penicillium glaucum_,
and gradually the urine becomes opalescent in consequence of these fungi
multiplying in great numbers in every part of the fluid. See URINARY
DEPOSITS (FUNGI).
“Diabetic urine has a sweet taste, and often numbers of flies are
attracted to it, which fact sometimes leads the patient to suspect that
the urine is not healthy.”[251]
[Footnote 251: ‘Kidney Diseases, Urinary Deposits,’ &c., Dr Lionel Beale.]
White merino, that has been wet with a solution of bichloride of tin, is
also said to form a ready test for sugar in urine.
Albumen in urine may be detected by the nitric acid, or by the heat test.
The nitric acid test is performed as follows.——Fill a test tube to about
an inch with the urine, then incline the tube and pour in strong nitric
acid down the side of the tube, so that the acid sinks to the bottom and
displaces the urine, which by reason of its smaller specific gravity rests
above it. Let the acid be added till it forms a stratum about a quarter of
an inch thick at the bottom.
If the urine contain albumen three layers will be perceptible——one,
perfectly colourless, of nitric acid at the bottom; immediately above this
an opalescent zone of the coagulated albumen; and, on the top, the
unaltered urine.
In his work, ‘Kidney Diseases and Urinary Deposits,’ Dr Lionel Beale
directs attention to the very important fact that “two or three drops of
nitric acid to about a drachm of albuminous urine in a test tube will
produce a precipitate of albumen which will be _dissolved on agitation_,
while, on the other hand, about half as much strong nitric acid as there
is of urine will redissolve the precipitate of albumen, unless the
quantity present be excessive. Albumen precipitated by nitric acid is
_soluble in weak nitric acid_, and in a considerable excess of urine, and
it is also _soluble in strong nitric acid_. _It is therefore necessary in
employing the nitric acid test to add from ten to fifteen drops of the
strong acid to about a drachm of the urine suspected to contain albumen._”
Dr Roberts gives the following directions for applying the heat test:——If
the urine have its usual acid reaction it becomes turbid on boiling when
it contains albumen, and this turbidity persists after the addition of an
acid. There are two points to be remembered on using heat alone as a test
for albumen. First, that albumen is not coagulated by heat when the urine
is alkaline; in such cases, therefore, it is necessary before boiling to
restore the acidity by a few drops of acetic acid (carefully avoiding
excess). Secondly, when the urine is neutral or very feebly acid, it may
become turbid on heating, from precipitation of the earthy phosphates, but
turbidity from this cause is easily distinguished from albumen by a drop
of nitric or acetic acid, which instantly causes the phosphates to
disappear. It may sometimes happen that the patient whose urine is to be
submitted to examination for albumen may be taking large doses of nitric
or hydrochloric acid. Under these circumstances Dr Bence Jones recommends
the addition of ammonia to the urine, nearly to the point of
neutralisation.
Mr Louis Siebold proposes a modification of Dr Roberts’s method of
applying the heat test in acid states of the urine, which is as
follows:——Add solution of ammonia to the urine until just perceptibly
alkaline, filter, and add diluted acetic acid very cautiously until the
urine acquires a faint acid reaction, avoiding the use of a single drop
more than is necessary. Now place equal quantities of this mixture into
two test tubes of equal size, heat one of them to ebullition, and compare
it with the cold sample contained in the other test tube. The least
turbidity is thus distinctly observed, and gives absolute proof of the
presence of albumen, the error of confounding phosphates with albumen
being out of the question, as they are precipitated by the ammonia and
removed by filtration.
M. Galipe[252] says the following is a delicate as well as trustworthy
test for albuminous urine. A few drops of the urine are carefully added to
a solution of picric acid contained in a small conical test glass. If
albumen be present a well-marked turbidity will be produced at the point
of contact between the two liquids. On applying heat the albumen
agglutinates, and rises to the surface. Phosphates and urates are said not
to interfere with this test.
[Footnote 252: ‘Pharm. Zeitung for Russland,’ xiv, 48 (‘Pharm. Journ.’).]
In order to determine the quantity of albumen in urine proceed as
follows:——Add a little acetic acid to the urine, and then heat it in a
water bath until it boils. Or the albuminous urine may be dropped into
boiling water acidulated with acetic acid. In either case collect the
precipitate on a weighed filter, wash it well, dry it, and weigh it. The
albumen must afterwards be incinerated, and the resulting residue, which
consists of earthy salts, must be deducted from the dried precipitate.
Stolnikow[253] adopts the following method for the quantitative estimation
of albumen in urine:——The urine is diluted with water until a sample
poured upon some nitric acid contained in a test tube produces still a
faint white ring at the point of contact after the lapse of forty seconds.
The number of volumes of water added to the volume of urine (which may be
taken as one) is divided by 250, and the quotient will be the percentage
of albumen in the urine. This relation has been established and confirmed
by gravimetric determinations.
[Footnote 253: ‘Chem. Central.’ (‘Pharm. Journ.’).]
It is sometimes desirable to remove the albumen from the urine before
proceeding to search for other substances. There are several methods of
accomplishing this. If the urine be boiled the albumen will become
coagulated, but in many cases it may happen, owing to the urine being
slightly alkaline or neutral, that a small quantity may remain in
solution. Hence it will be advisable to add a little acetic acid to the
urine before applying heat to it, to remove the precipitated matters by
filtration, and to exactly neutralise the acid in the filtrate. If a few
crystals of sulphate of soda be heated with albuminous urine, the albumen
and allied matters may be entirely removed without injury to other organic
matters dissolved, and without interfering with the employment of other
reagents. When it is desirable to free the urine from albumen previous to
testing for sugar, this latter method will be found the best and most
convenient.
The following analyses represent the amount of albumen present in the
urine of two patients suffering from Bright’s disease:
No. 1 (Simon).
Specific gravity 1014·
Water 966·10
Solid constituents 33·90
Urea 4·77
Uric acid 0·40
Fixed salts 8·04
Extractive matters 2·40
Albumen 18·00
No. 2 (Dr Percy).
Specific gravity 1020·
Water 946·82
Solid constituents 53·18
Urea 7·68
Uric acid, and indeterminate }
animal matter } 17·52
Fixed soluble salts 5·20
Earthy phosphates 0·14
Albumen 22·64
Dr Parkes records the case of a patient suffering from albuminuria, who
excreted 545 grains of albumen in twenty-four hours. See URATES.
Urine frequently contains an abnormally large quantity of urea. Such urine
is of high specific gravity——1·030 or more. When present in large excess
the urea becomes deposited in ‘sparkling crystalline lamellæ’ of the
nitrate, if it be mixed with an equal quantity of strong nitric acid in
the cold.
The crystals vary slightly in character, according to the amount of nitric
acid employed and the degree of concentration of the urine. Urine which
thus yields, without previous concentration, the nitrate, is said to
contain an excess of urea. See page 1689.
The quantity of urea present in urine is best determined by a process
invented by Liebig. When a solution of pernitrate of mercury is added to
one of pure urea the urea and mercuric salt unite and form an insoluble
compound, of undetermined constitution. If, however, the chlorides of the
alkalies and alkaline earths are present, this combination does not take
place, owing to the decomposition of the mercuric nitrate, and the
formation of bichloride of mercury, and a nitrate of the alkali or
alkaline earth, both of which are soluble. When, however, the
decomposition of the chloride has been completed, the urea may be entirely
precipitated, provided a sufficient quantity of mercuric nitrate be added
to the solution. In estimating the amount of urea in urine, therefore, it
is only necessary to add to the urine a solution of the mercuric salt of
known strength, since from the quantity of this latter which has been
employed in throwing down the urea, this can easily be calculated.
In performing this analysis, three special solutions are requisite:
1. A solution consisting of one part by measure of a cold saturated
solution of barium nitrate with two parts (also by measure) of saturated
baryta water. This serves for the removal of the phosphates and sulphates,
the presence of which in the urine would interfere with the analysis.
2. The standard solution of mercuric nitrate, which is made as
follows:——772 grains of red oxide of mercury placed in a beaker are
dissolved in a sufficient quantity of nitric acid (sp. gr. 1·20) by a
gentle heat, and evaporated over a water bath until all _excess of free
acid_ is driven off. This may be known by the liquid becoming dense and
syrupy in appearance. It is then poured into a properly graduated vessel
and diluted to 10,000 grain-measures. Of this solution, 10
grain-measures = 0·1 grain of urea.
3. A solution of carbonate of soda in distilled water, 20 grains to the
ounce. This solution is employed to indicate when the titration is
complete, and to show the operator that all the urea has been precipitated
by the mercuric salt.
The operation is thus performed:
(_a._) 400 grain-measures of the clear urine are mixed with 200
grain-measures of the baryta solution, No. 1. The mixture is poured into a
filter, and of the clear filtrate which passes through 150 grain-measures
are carefully measured off, and poured into a small beaker. This quantity
of course contains two thirds, or 100 grain-measures of wine.
(_b._) A graduated burette (each division of which equals a grain-measure
of water) is next filled with the solution (No. 2) of mercuric nitrate,
which is then dropped into the beaker containing the filtered urine, until
the mixture becomes turbid. The quantity of solution that has been
required to just reach the point of turbidity is then noted down; it shows
that all the chloride of sodium has been decomposed, and that the urea is
now beginning to precipitate.
(_c._) The solution (No. 2) is now added more liberally, and thoroughly
mixed with the contents of the beaker by means of a glass rod; a copious
white precipitate is being formed. The operation is completed, when, of
course, no more precipitate is thrown down.
(_d._) This point is ascertained by means of the solution of carbonate of
soda (No. 3), to a few isolated drops of which dotted about a white plate,
or slab, or placed on a watch glass, give, when mixed by means of the
stirring rod with a drop of the turbid mixture from the beaker, a yellow
tinge, owing to the formation of hydrated oxide of mercury.
(_e._) The quantity of solution of mercuric nitrate that it has taken to
produce the above reaction is then noted down, and from this the portion
used before the occurrence of the turbidity is deducted, the remainder, of
course, being the amount required to precipitate the urea. By bearing in
mind the statement already made that 10 grain-measures of the mercurial
solution indicate 0·1 grain of urea, the quantity excreted in 24 hours may
be arrived at by a very easy and obvious calculation.
_Dr Davy’s method of estimating Urea._ This consists in the decomposition
of a known quantity of urine by sodium hypochlorite, the amount of urea
being calculated from the resulting nitrogen. A glass tube, 12 or 14
inches in height, and graduated to tenths and hundredths of a cubic inch,
is filled to more than a third of its length with mercury; a measured
quantity of urine, varying from a quarter of a drachm to a drachm, is next
poured into the tube, which is then filled up with a solution of sodium
hypochlorite (the liquor sodæ chlorinatæ of the Dublin Pharmacopœia). This
latter must be poured in quickly, and the open end of the tube immediately
closed with the thumb. The tube is then shaken to ensure admixture between
the urine and hypochlorite, and stood with the open end downwards in a cup
filled with a saturated solution of common salt; the mercury escapes into
the tube, its place being filled by the solution of salt, which being
heavier than the mixture of urine and hypochlorite, retains them in the
upper part of the tube. The urine becomes soon decomposed, the carbonic
acid, which is one of the products of its decomposition, being absorbed by
the excess of chloride of sodium present, whilst the liberated nitrogen
bubbles up to the top of the tube. When no more evolution of gas takes
place, the volume of nitrogen is read off, and from its amount the
quantity of urea present in the amount of urine experimented upon is
calculated: one-fifth of a grain of urine = 0·3098 parts of a cubic inch of
nitrogen at 60° Fahr. and 30” barometric pressure.
_Haughton’s method of estimating Urea from the specific gravity of the
Urine._ After having measured the urine voided during 24 hours, and
determined the specific gravity of the whole collected amount, and then
consulting the accompanying table, compiled by Professor Haughton, the
number of grains of urea excreted per diem is immediately ascertained.
This quantity will be shown by the figures which stand at the points where
the lines running respectively from the number of fluid ounces and the
‘specific gravity’ intersect each other. Thus, suppose the daily amount of
urine to have been 30 ounces, and the specific gravity 1006, the number of
grains of urea contained in it will be 85. This method is inserted for
urines containing sugar and albumen.
_Determination of the Water._ The amount of water in any sample of urine
may be determined by weighing 1000 grains of the recently excreted urine
into a counterpoised platinum or porcelain dish, and ascertaining the loss
it has undergone after evaporation to dryness. The operation should be
performed as speedily as possible. The best plan is to concentrate the
urine in a water bath, the evaporation should be continued _in vacuo_ over
strong sulphuric acid, until the weight of the residue remains constant.
By way of control, another sample of the same urine, consisting of 500
grains, may be operated upon at the same time, and under the same
conditions.
URINARY DEPOSITS, &c. These differ from the albumen, sugar, bile, &c.,
previously described, in being insoluble in abnormal urine. Sometimes
they are diffused throughout the whole body of the urine, when they give
it an opaque appearance. Sometimes they may be met with floating on its
surface; at others they are only partially diffused through the fluid,
frequently in the form of a transparent or opaque cloud, when they occupy
a considerable space; whilst very often they occur in a crystalline or
granular form, deposited sometimes at the bottom and sometimes at the
sides of the vessel holding the urine.
Of the numberless insoluble substances met with in urine, both in health
and disease, our limits will only permit us to notice those which are most
important, and of frequent occurrence.
For the detection of the generality of these the microscope is
indispensable. An instrument magnifying 200 to 220 diameters (1/4 of inch
objective) will generally be found sufficiently powerful, and in some
instances an inch objective, magnifying 40 diameters (as in the larger
forms of crystalline deposit) will answer all the purposes.
Some of the varieties of these deposits admit of a double examination,
viz. a microscopical and chemical one. When this is the case, the
particulars applying to each kind of investigation will be given.
_Mucus._ Mucus is always present in small quantity in healthy urine, in
which it shows itself within a few hours after the urine has been excreted
in the shape of a transparent cloud towards the bottom of the vessel
containing the urine.
_Pus._ The presence of pus in urine is indicated by an opaque, more or
less bulky, cream-like deposit at the bottom of the vessel holding the
urine, to which some separated pus globules, finding their way to the
supernatant liquid, give an appearance of slight turbidity. By shaking the
vessel the whole of the liquid becomes turbid, owing to the equal
dissemination through it of the pus globules. The pus again deposits on
standing. A small quantity of albumen is always met with in the clear part
of urine which contains pus; the albumen being derived from the _liquor
puris_, the liquid by which the pus-corpuscles are surrounded.
Whenever it can be obtained in sufficient quantity, pus should always be
examined chemically, as follows:——The supernatant urine being decanted,
the suspected sediment is shaken up with liquor potassæ, when if it become
converted into a gelatinous, viscid substance, incapable of being dropped
from the tube, and when poured from it running as a slimy and almost
continuous mass, it may be pronounced pus. This same gelatinous viscid
mass is met with in alkaline urines containing pus, adhering to the sides
of the vessel in which the urine is placed, where it has been formed by
the action of the carbonate of ammonia (caused by the decomposition
of the urea) upon the pus. The reaction upon the pus is the same as that
which takes place when liquor potassæ is employed. The stringy viscid
substance due to the last cause is frequently, but erroneously, termed
_mucus_.
Professor HAUGHTON’S _Table for the Estimation of the
Daily Excretion of Urea from the Specific Gravity_.
-------+-----------------------------------------------------------
Fluid | Specific
Ounces.| Gravity.
+----+----+----+----+----+----+----+----+----+----+----+----+----
|1003|1004|1005|1006|1007|1008|1009|1010|1011|1012|1013|1014|1015
-------+----+----+----+----+----+----+----+----+----+----+----+----
20| 35| 36| 43 | 57 | 71 | 85 | 100| 103|106 | 119| 130| 136| 142
22| 38| 40| 47 | 62 | 78 | 95 | 110| 113|116 | 130| 149| 142| 156
24| 42| 43| 51 | 68 | 85 |101 | 120| 123|127 | 142| 156| 163| 170
26| 45| 47| 55 | 73 | 92 |110 | 130| 131|137 | 153| 169| 176| 184
28| 48| 50| 59 | 79 | 99 |118 | 140| 144|148 | 165| 182| 190| 198
30| 52| 54| 64 | 85 |106 |127 | 150| 155|159 | 177| 195| 204| 213
32| 55| 57| 68 | 90 |113 |135 | 160| 165|169 | 188| 208| 217| 227
34| 58| 61| 72 | 96 |120 |144 | 170| 175|180 | 200| 221| 231| 241
36| 61| 64| 76 |102 |127 |153 | 180| 185|191 | 212| 234| 244| 255
38| 65| 68| 80 |108 |134 |161 | 190| 195|201 | 224| 247| 258| 269
40| 69| 72| 85 |114 |142 |170 | 200| 206|212 | 236| 260| 272| 284
42| 74| 75| 89 |119 |148 |178 | 210| 216|222 | 247| 273| 285| 298
44| 76| 79| 93 |125 |156 |186 | 220| 226|233 | 259| 286| 299| 312
46| 80| 82| 96 |130 |163 |195 | 230| 236|243 | 271| 299| 312| 326
48| 84| 86|101 |136 |170 |203 | 240| 246|254 | 283| 312| 326| 340
50| 87| 90|106 |142 |178 |212 | 250| 257|265 | 295| 325| 340| 355
52| 90| 94|110 |147 |185 |220 | 260| 267|276 | 307| 338| 353| 369
54| 94| 98|114 |153 |192 |229 | 270| 277|286 | 319| 351| 367| 383
56| 96| 100|119 |159 |199 |238 | 280| 288|297 | 331| 364| 380| 397
58| 100| 104|123 |165 |206 |246 | 290| 298|308 | 343| 377| 394| 411
60| 104| 108|128 |171 |213 |255 | 300| 309|310 | 355| 391| 408| 426
62| 108| 110|132 |176 |220 |263 | 310| 319|329 | 404| 421| 440| 468
64| 110| 114|136 |182 |227 |271 | 320| 329|340 | 378| 417| 435| 454
66| 114| 118|140 |187 |234 |280 | 330| 340|351 | 390| 431| 448| 468
68| 116| 122|144 |193 |240 |288 | 340| 350|361 | 402| 443| 462| 482
70| 120| 126|149 |199 |248 |297 | 350| 361|372 | 414| 456| 476| 497
72| 122| 128|153 |204 |255 |305 | 360| 371|382 | 425| 469| 489| 511
74| 126| 132|157 |210 |262 |314 | 370| 381|393 | 437| 482| 503| 525
76| 130| 136|161 |216 |269 |323 | 380| 391|404 | 449| 595| 516| 539
78| 134| 140|165 |222 |276 |331 | 390| 401|414 | 461| 508| 530| 553
80| 139| 144|170 |228 |284 |340 | 400| 412|445 | 473| 521| 544| 568
——+----+----+----+----+----+----+----+----+----+----+----+----+----
-------+-----------------------------------------------------------
Fluid | Specific
Ounces.| Gravity.
+----+----+----+----+----+----+----+----+----+----+----+----+----
|1016|1017|1018|1019|1020|1021|1022|1023|1024|1025|1026|1027|1028
-------+----+----+----+----+----+----+----+----+----+----+----+----
20| 151| 160| 196| 233| 241| 249| 257| 265| 274| 276| 278| 279| 280
22| 166| 176| 215| 257| 265| 274| 282| 292| 301| 303| 305| 306| 308
24| 181| 192| 235| 280| 289| 299| 308| 319| 329| 331| 333| 334| 336
26| 196| 208| 254| 303| 313| 324| 334| 346| 356| 359| 360| 362| 364
28| 221| 224| 274| 326| 337| 349| 360| 372| 383| 386| 388| 390| 392
30| 226| 240| 294| 349| 361| 374| 386| 399| 411| 414| 416| 418| 420
32| 241| 256| 313| 373| 385| 398| 411| 425| 438| 442| 443| 446| 448
34| 256| 272| 333| 396| 409| 423| 437| 451| 466| 469| 471| 474| 476
36| 271| 288| 352| 419| 433| 448| 462| 477| 493| 497| 499| 502| 504
38| 286| 304| 372| 442| 457| 473| 488| 503| 520| 524| 527| 530| 532
40| 302| 320| 392| 465| 484| 498| 514| 530| 548| 552| 555| 558| 560
42| 317| 336| 411| 489| 506| 523| 540| 557| 575| 580| 582| 585| 588
44| 332| 352| 431| 512| 530| 548| 556| 584| 603| 607| 610| 613| 616
46| 347| 368| 450| 535| 554| 573| 592| 611| 630| 635| 638| 641| 644
48| 362| 384| 470| 558| 578| 598| 618| 637| 657| 662| 666| 669| 672
50| 377| 400| 490| 581| 602| 623| 644| 665| 685| 690| 694| 697| 700
52| 393| 416| 509| 605| 626| 648| 669| 692| 711| 718| 721| 724| 728
54| 408| 432| 529| 628| 650| 673| 695| 718| 740| 745| 749| 752| 756
56| 423| 448| 548| 651| 674| 698| 720| 745| 767| 772| 776| 780| 784
58| 438| 464| 568| 674| 698| 723| 746| 772| 794| 800| 804| 808| 812
60| 453| 480| 588| 697| 722| 748| 772| 798| 822| 828| 832| 836| 840
62| 496| 607| 719| 746| 772| 797| 824| 849| 856| 859| 864| 864| 868
64| 483| 512| 627| 742| 770| 797| 823| 851| 877| 883| 887| 862| 896
66| 498| 528| 646| 766| 794| 822| 849| 877| 904| 911| 915| 920| 924
68| 513| 544| 666| 790| 818| 847| 875| 904| 931| 939| 943| 948| 954
70| 528| 560| 686| 814| 843| 872| 901| 930| 959| 966| 971| 976| 980
72| 544| 576| 705| 838| 867| 896| 926| 956| 986| 994| 998|1004|1008
74| 558| 592| 725| 861| 891| 921| 951| 982|1014|1021|1026|1032|1036
76| 573| 608| 745| 884| 915| 946| 977|1008|1041|1049|1054|1060|1064
78| 588| 624| 765| 907| 939| 971|1002|1034|1068|1076|1082|1088|1092
80| 604| 640| 785| 930| 964| 996|1028|1060|1096|1104|1110|1116|1120
——+----+----+----+----+----+----+----+----+----+----+----+----+----
In urines containing pus, the clear portion should always be examined for
albumen, since where this is found, except in small amount, some form of
kidney disease may be suspected.
But it sometimes happens that the pus is present in such small quantity in
the urine as to preclude its chemical examination. Under these
circumstances, recourse must be had to the microscope. Dr Lionel Beale
says, “Pus-globules, which have been long removed from the body, always
have a granulated appearance in the microscope, and, when fresh, do not
always exhibit a well-defined nucleus; the outline is usually distinct and
circular, but it is finely crenated. Upon the addition of acetic acid the
globule increases somewhat in size, becomes spherical, with a smooth,
faint outline, and from one to four nearly circular bodies are developed
in the centre of each. If the pus-corpuscles have lain some days in the
urine they will have undergone complete disintegration.”
_Epithelium._ A great many varieties of epithelium, derived from different
parts of the kidneys, ureters, bladder, urethra, vagina, &c., are more or
less present in urine. A few of these are given in the accompanying
engraving. In the various diseases peculiar to the urinary and
genito-urinary organs the quantity of epithelium present in the urine is
frequently considerable, and as in some cases it presents itself in an
imperfect or disintegrated form, its identification, except to the
experienced microscopist and physiologist, becomes a matter of great
difficulty.
_Casts._ Casts or moulds which have been formed in the tubes of the
kidneys, or in the uterus and vagina, are constantly finding their way
into the urine of persons affected with acute or chronic renal diseases
and uterine affections. They are very varied both in character and
appearance, and difficult of recognition, except by the skilled
microscopist and pathologist.
_Blood-corpuscles._ These, when present in quiescent urine, occur as a
sediment at the bottom of the vessel. Some few globules, however, are
diffused throughout the supernatant urine, and impart to it a smoky
appearance, if the fluid have a marked acid reaction; whereas if the
reaction be alkaline the corpuscles assume a bright red colour.
In the accompanying plate the three upper groups represent
blood-corpuscles taken from the human body; the three lower those found in
urine. Of these latter some will be seen to have lost their circular
outline, and to have become jagged or crenated. In some cases, on the
contrary, they swell and become much enlarged. These changes in appearance
take place when the blood has remained for some time in the urine, and
appear to be due to the forces of endosmose and exosmose.
[Illustration: (Beale.)]
_Fungi._ The chief vegetable organisms found in urine are the _sugar
fungus_ and the _Penicillium glaucum_. The sugar fungus is precisely the
same as the yeast plant (the _Torula cerevisiæ_). The _Penicillium_ is
very frequently present in albuminous urine, with an acid reaction, as
well as in diabetic.
_Uric acid._ See back.
_Urates._——According to Bence Jones the soluble urates met with in healthy
urine consist of uric acid, potassium, ammonium, and sodium.
In abnormal urine the urates of ammonium and sodium sometimes occur, the
latter, which are the more general, presenting under the microscope the
appearance shown below.
[Illustration: (Beale.)]
Urate of sodium is, however, much more common in the urine of children
than of adults, when it presents itself in the form of spherical crystals.
In both cases the urates are associated with uric acid (resulting from
their partial decomposition), represented by the small spiked crystals
protruding from the spheres in the form of needle-shaped crystals. Urate
of sodium occurs as the concretions known as ‘chalk stones’ in gout. But
by far the most abundant kind of urates met with in abnormal urine is that
known as _amorphous urates_, which constitute the most common variety of
urinary deposits.
[Illustration: Urate of soda in a globular form commonly found in the
urine of children.]
Heintz states that they are a mixture of urate of sodium with small
quantities of the urates of ammonium, lime, and magnesium. They are very
frequently seen in the urine of persons in excellent health, in which,
owing perhaps to too abundant or nitrogenous diet and an insufficiency of
muscular exercise, being in excess, they are thrown down when the urine
cools.
An excess of the amorphous urates in urine, like the presence of pus and
phosphates, is indicated by the bulky precipitate more or less diffused
throughout the vessel containing the urine. A very easy test will decide
as to which of the three classes of substances (if only one of them be
present) the precipitate belongs. The supernatant fluid being decanted
from the deposit, about an equal bulk of liquor potassæ is added to the
latter, when one of three results will ensue:
1. If it be _pus_, and become viscid, it will exhibit the qualities
already mentioned under the description of that substance.
2. If _phosphates_, no alteration will ensue.
3. If _amorphous urate_, it will at once dissolve.
When amorphous urates are uniformly distributed throughout the urine they
give it a milky appearance, which may sometimes lead to its being mistaken
for _chylous_ urine, or urine throughout which fatty particles of chyle
are diffused. This latter doubt, however, may be easily set at rest by
gently heating it. If the turbidity is owing to the urate it will
disappear; if to chyle it will remain.
If the amorphous urate be decomposed by a little hydrochloric acid, it
will yield uric acid, easily recognised by its characteristic form under
the microscope, or when treated with nitric acid and ammonia, will answer
to the murexed test.
It sometimes happens that in testing an acid urine suspected to contain
albumen, the urine may contain so large an amount of uric acid in solution
that, upon adding a drop of nitric acid to it, a bulky precipitate of uric
acid, exactly resembling albumen, is thrown down, and it may be
erroneously regarded as this substance if examined under the microscope
immediately upon its formation. Upon being allowed, however, to stand some
time, and then placed under the microscope, the well-known crystals of the
acid will reveal themselves.
In such urine no precipitate takes place when the liquid is heated,
another essential feature in which it diverges from albumen.
_Phosphates._——The urinary earthy phosphates occur under two varieties,
viz. the phosphate of ammonia and magnesia, known as the triple phosphate,
and the phosphate of lime.
In the engravings below, the principal crystalline forms of the triple
phosphate are shown.
[Illustration: FIG. 1.——Crystals of triple phosphate with spherules of
urate of soda. (Beale.)]
[Illustration: FIG. 2.——Crystals of triple phosphate with triangular
prisms, with truncated extremities. (Beale.)]
Of these the triangular prismatic, with the truncated extremities, is the
most common. In some cases the prisms are so much reduced in length as to
resemble the octahedral crystals of oxalate of lime, for which they are
sometimes mistaken by the inexperienced. When any doubt exists on this
point it must be set at rest by having recourse to the chemical tests
given further on. The triple phosphate is rarely met with alone, urate of
ammonia, and sometimes uric acid and oxalate of lime, being present,
although generally occurring in neutral or alkaline urine. The triple acid
is sometimes found in that which is acid.
When ammonia is added to fresh urine the triple phosphate is precipitated,
and if it be then examined by the microscope it will be found to consist
of beautiful stellate crystals, and to form a most attractive object. The
presence of phosphoric acid can be demonstrated by the ordinary reagents.
Phosphate of lime dissolves in strong acids without effervescence. The
presence of lime, as well as of phosphoric acid, can easily be verified by
the usual tests.
_Oxalate of lime._ The principal crystalline forms of oxalate of lime,
when it occurs as a urinary deposit, are the octahedral and the dumb-bell.
Of these the most common is the octahedral. These octahedra (which have
one axis much shorter than the other two) vary considerably in size, but
there is reason to believe that the diversity in appearance which they
exhibit is due to crystals of precisely the same shape occupying
different positions as to the direction of their axes, when examined by
the microscope. There are a great many diversities of the dumb-bell form
of oxalate of lime, which seem to be derived from circular and oval
crystals. The subjoined cuts illustrate the varieties of crystalline
oxalates the most generally met with. When the crystals of oxalate are
extremely minute, they are very liable to be overlooked, since they then
appear as almost opaque cubes, and may not unnaturally be taken for urate
of soda, to which they bear no slight resemblance; but from which they
differ by being insoluble in potash or acetic acid, and not dissolving on
the application of heat. We have already alluded to their resemblance to
the dumb-bells of the earthy phosphates. Another distinctive feature is
that the oxalates rarely sink to the bottom of the vessel, but are
diffused through the mucous cloud, which forms in urine after a short
time.
[Illustration: Oxalate of lime. (Beale.)]
[Illustration]
_Cystine._ Cystine is an occasional ingredient in urine, when it occurs as
a whitish precipitate crystallised in hexagonal plates. At other times,
but not so frequently, it is met with dissolved in the urine. It may be
separated from the urine holding it in solution by the addition of an
excess of acetic acid. Under the microscope cystine bears somewhat of a
resemblance to uric acid, from which, however, it differs when under
treatment with ammonia. When ammonia is added to cystine the cystine
dissolves, but by the spontaneous evaporation of the ammonia remains
behind in its original form; whilst, if the ammonia be allowed to escape
under the same circumstance from the urate of ammonia which has been
formed, this remains behind as an amorphous mass. Ammonia, therefore,
dissolves the cystine without entering into chemical union with it. Potash
also readily dissolves cystine, as do also oxalic acid and the strong
mineral acids. It is, however, insoluble in boiling water, in weak
hydrochloric acid, and, as we have seen, in acetic acid.
_Obs._ In the examination of urine it is important that the investigation
should be conducted upon a portion taken from _the whole of the urine
excreted during twenty-four hours_, and not on an isolated quantity voided
at any particular time.
The compiler of the present article has to acknowledge his indebtedness to
Dr Lionel Beale’s very valuable and exhaustive work, ‘Kidney Diseases,
Urinary Deposits, &c.,’ as well as to Dr W. Roberts’s excellent book,
‘Urinary and Renal Diseases,’ to both of which volumes the reader,
desirous of further and more explicit information on the subject, is
referred.
=URINOM′ETER.= An hydrometer adapted to determining the density of urine.
That of Dr Prout is the simplest and best. Urinometers should always be
tested by placing them in distilled water at 60° Fahr. from 1·015 to 1·025
Beale.
=URN POWDER.= Crocus martis, or jeweller’s rouge.
=URTICAR′IA.= See RASH.
=US′QUEBAUGH.= _Syn._ ESCUBAC. Literally, mad water, the Irish name of
which, ‘whisky,’ is a corruption. At the present time it is applied to a
strong cordial spirit, much drunk in Ireland, and made in the greatest
perfection at Drogheda.
_Prep._ 1. Brandy or proof spirit, 3 galls.; dates (without their kernels)
and raisins, of each, bruised, 1/4 lb.; juniper berries, bruised, 1 oz.;
mace and cloves, of each 3/4 oz.; coriander and aniseed, of each 1/2 oz.;
cinnamon, 1/4 oz.; macerate, with frequent agitation, for 14 days, then
filter, and add of capillaire or simple syrup, 1 gall.
2. Pimento and caraways, of each 3 oz.; mace, cloves, and nutmegs, of each
2 oz; aniseed, corianders, and angelica root, of each 8 oz.; raisins,
stoned and bruised, 14 lbs.; proof spirit, 9 galls.; digest as before,
then press, filter, or clarify, and add of simple syrup, q. s. Should it
turn milky, add a little strong spirit, or clarify it with alum, or filter
through magnesia.
_Obs._ Usquebaugh is either coloured yellow with saffron (about 1/4 oz.
per gall.), or green with sap-green (about 1/2 oz. per gall.); either
being added to the other ingredients before maceration in the spirit.
=UVA URSI.= The _Arctostaphylus Uva Ursi_ (the Bearberry) is an indigenous
plant, the leaves of which are employed in medicine. Bearberry leaves
contain a large percentage of tannic acid, with a small quantity of gallic
acid, some resin, and a little volatile oil and extractive, together with
a crystallisable principle named _arbutin_, which is said to be a very
powerful diuretic. Another crystallisable resinous body named _arbutin_
has also been discovered in them. Bearberry leaves either in the form of
powder, infusion, or extract, are chiefly used in chronic diseases of the
bladder, in which there is an abnormal secretion of mucus, such as
_catarrhus vesicæ_, but neither acute nor active inflammation.
=VACCINA′TION.= See COW-POX. (POX.)
=VAC′CINE MATTER.= _Syn._ LYMPHA VACCINIÆ, L. This is collected either
upon the points of lancet-like pieces of ivory, or by opening the pustule,
and applying a small glass ball and tube (like those called by the boys in
London candle-pops, or fire-pops) to the orifice, expelling part of the
air in the ball by bringing a lighted taper near it; then, withdrawing the
taper, the matter is sucked into the ball, in which it may be sealed up
hermetically or cemented, and thus kept for a length of time. It is,
however, now generally preserved between two small pieces of glass, or in
straight capillary glass tubes. It is said that cotton thread is a
convenient and efficient vehicle. The matter may be liquefied with a
little clean water before application. A degree of heat scarcely higher
than that of the blood lessens its efficacy.
=VAC′UUM.= Empty space; a portion of space void of matter. For
experimental and manufacturing purposes, a sufficient vacuum is produced
either by means of the air-pump, or by filling an inclosed space by steam,
which is then condensed by the application of cold. Evaporation proceeds
much more rapidly, and liquids boil at much lower temperatures in an
exhausted receiver than when exposed to the air. Thus, under ordinary
circumstances, in the air, ether boils at 96°, alcohol at 177°, and Water
at 212° Fahr.; but in vacuo water boils at about 88°, alcohol at 56°, and
ether at -20° Fahr. In the best vacuum obtainable by a powerful air-pump,
water placed over oil of vitriol, to absorb the aqueous vapour as it
forms, will often enter into violent ebullition whilst ice is in the act
of formation on its surface. The reduction of the boiling-point with
reduced pressure is practically taken advantage of by the pharmaceutist in
the preparation of extracts, by the sugar refiner in the evaporation of
his syrups, by the distiller in the production of certain liqueurs, and by
the chemist in a variety of processes of interest or utility. See
EXTRACTS, EVAPORATION, REFRIGERATION, &c.
=VALE′′RIAN.= _Syn._ VALERIANÆ RADIX (B. P.), VALERIANÆ RADIX, VALERIANA
(Ph. L. E. & D.), L. “The root of the wild plant _Valeriana officinalis_
(Linn.), or wild valerian.” (Ph. L.) An excitant, antispasmodic, tonic,
and emmenagogue, not only acting on the secretions, but exercising a
specific influence over the cerebro-spinal system, and in large
quantities producing agitation, mental exaltation, and even
intoxication.——_Dose_, 10 to 30 or 40 gr., thrice daily; in hysteria,
epilepsy, headache (affecting only one side), morbid nervous sensibility,
&c. Even the odour of it exerts a species of fascination over cats.
=VALERIAN′IC ACID.= HC_{5}H_{9}O_{2}. _Syn._ VALERIC ACID; ACIDUM
VALERIANICUM, A. VALERICUM, L. _Prep._ 1. A mixture of potato oil or
corn-spirit oil (hydrated oxide of amyl) with about 10 times its weight of
quicklime and hydrate of potassa in equal proportions, placed in a glass
flask, is kept heated to about 400° Fahr., for 10 or 12 hours, by means of
a bath of oil or fusible metal; the nearly white solid residuum is mixed
with water, an excess of sulphuric acid added to the mixture, and the
whole subjected to distillation; the distillate is supersaturated with
potassa, evaporated nearly to dryness, to dissipate any undecomposed
potato oil, and then mixed with weak sulphuric acid in excess; a light
oily liquid (terhydrated valerianic acid) separates, which by cautious
rectification, yields at first water containing a little acid, and
afterwards pure monohydrated valerianic acid, which is perfectly identical
with that prepared from valerian root.
2. (Ph. D.) See VALERIANATE OF SODIUM. This is a most economical process.
_Prop., &c._ A limpid oily liquid, smelling strongly of valerian root; it
has an acid taste and reaction, and leaves a sensation of sweetness and a
white spot on the tongue; is inflammable; boils at 347°; is freely soluble
in alcohol and ether; dissolves in 30 parts of water, and forms salts
called valerianates, most of which have a sweetish taste, are soluble, and
uncrystallisable; sp. gr. ·937; placed in contact with water, it absorbs a
portion of it, and is converted into the terhydrated acid, with increase
of sp. gr., and reduction of the boiling-point.
=VALE′′RIC ACID.= See VALERIANIC ACID.
=VALO′NIA.= The cup of a large species of acorn, imported from the Levant.
Used in tanning leather.
=VANAD′IC ACID.= V_{2}O_{2}. _Syn._ VANADIC ANHYDRIDE, TEROXIDE OF V.;
ACIDUM VANADICUM, L. _Prep._ (Johnston.) From the native vanadate of lead,
by dissolving it in nitric acid, passing sulphuretted hydrogen through the
solution, to throw down lead and arsenic, filtering, and evaporating the
resulting blue liquid to dryness; the residuum is then dissolved in a
solution of ammonia, and a piece of sal ammoniac, considerably larger than
can be dissolved, introduced; as the latter dissolves, a pulverulent
precipitate of vanadate of ammonium is formed, which must be washed, first
in a solution of sal ammoniac, and then in alcohol of ·860; by exposing
this salt, in an open platinum crucible, to a heat a little below redness,
and keeping it constantly stirred, until it acquires a dark red colour,
pure vanadic acid is obtained.
_Prep., &c._ Vanadic acid is orange coloured, scarcely soluble in water,
and forms, with the alkaline bases, soluble salts called vanadates; and
with the other bases sparingly soluble salts. All of these have an orange
or yellow colour. “Vanadate of ammonia mixed with solution of galls forms
a black fluid, which is the best writing ink hitherto known. The quantity
of salt required for this purpose is very small; the writing is perfectly
black, and not obliterated by alkalies, acids, chlorine, or other
reagents,” (Ure.)
=VANA′DIUM.= V. A rare metal discovered by Sefstom, in 1830. in some
Swedish iron extracted from an iron mine near Jönköping. It has since been
found in a Vanadinite lead ore met with in Scotland, Zimpanan in Mexico,
and Chili, and in the iron slag of Staffordshire. Of late years a more
abundant source of Vanadium has been discovered by Professor Roscoe in the
cupriferous stratum of the New Red Sandstone at Alderley Edge in Cheshire.
There are four, and possibly five oxides of this element.
=Vanadic oxychloride.= _Syn._ VANADIC OXYTRICHLORIDE. (VOCl_{3}.) Roscoe
states there are several oxychlorides of vanadium, which, however, have
not been studied. The most interesting of them is the oxytrichloride,
which corresponds to the phosphorous oxychloride. This oxytrichloride is a
yellow fuming liquid, which is instantly decomposed by water into vanadic
and hydrochloric acids. The oxytrichloride may be obtained by heating
vanadic anhydride and charcoal (mixed together) in a current of hydrogen,
after which it is heated in a current of dry chlorine. An easier method is
by passing dry chlorine over the sesquioxide of vanadium.
=Vanadic pentoxide.= _Syn._ VANADIC ANHYDRIDE (V_{2}O_{5}.). At a red hot
heat this oxide fuses, and on cooling, crystallises in rhombic prisms. It
is but little soluble in water; the aqueous solution, which is of a yellow
tint, is strongly acid, and produces a marked reddening effect on litmus.
Vanadic anhydride forms both normal and acid salts. The ammonic vanadiate
(Roscoe’s meta vanadiate) is the chief source of the acid. This salt may
be obtained by adding pieces of sal ammoniac to a crude solution of
potassic vanadiate, the resulting ammonic vanadiate being insoluble in a
saturated solution of sal ammoniac, is deposited in small crystalline
grains. The vanadic anhydride may be obtained from the ammonic vanadiate
by heating an aqueous solution of the salt in the open air, when the
ammonia is driven off, and the vanadic anhydride is left behind. The acid
ammonic vanadiate, mixed with tincture of galls, makes a very durable
writing ink, unacted upon either by alkalies or chlorine. Acids turn such
blue without, however, destroying it.
=Vanadic triox′ide.= (V_{2}O_{2}.), is the _Vanadyl_ of Roscoe, who
obtained it in the form of a grey metallic-looking powder, by the
transmission of a current of dry hydrogen charged with the vapours of
oxychloride of Vanadium, through a tube containing ignited charcoal. It
dissolves in dilute acids, with evolution of hydrogen. Solutions of its
salts are lavender coloured. Berzelius regarded this oxide as a metal.
_Tests._ The vanadiates mostly occur of a red or yellow colour. When
treated with sulphuretted hydrogen, they yield a solution of a fine blue
colour, a reaction that distinguishes them from the chromates, which,
under similar treatment, would give a green liquid. When mixed with borax
and exposed to the reducing flame of the blowpipe, compounds containing
vanadium give a green glass, which turns to yellow in the oxidizing flame.
Professor Roscoe, to whose researches we are indebted for all the chemical
knowledge we possess respecting vanadium, says:——“All the main facts now
established in connection with the chemical department of this element
proved it to bear a strong analogy to the elements phosphorus and arsenic;
in fact, it occupied a previously vacant place in a well-defined group of
triad, or, as some chemists prefer to consider them, pentad elements.
There was a property of vanadium in virtue of which it might ultimately
obtain considerable importance in the arts, though in the present infancy
of the history of the metal it was difficult to foretell this with any
certainty. This property was the power of forming a permanent black for
dyeing purposes. The black produced by the action of vanadium had the
advantage over copper and aniline blacks, viz. that it was permanent,
whereas the latter were liable to turn green. This application of an
element that was first introduced into notice as a chemical curiosity
furnished one more example of the importance of original scientific
investigation. However far a newly discovered substance might seem to be
removed from purposes of practical utility, we never know at what moment
it might be turned to account for the benefit of the human race.”
=VANIL′LA.= _Syn._ VANILLE, Fr. The dried pods of various species of
Vanilla, a genus of the natural order _Orchidaceæ_. It is chiefly used in
the manufacture of chocolate and perfumery. As a medicine it is much
employed on the Continent as an aromatic stimulant and neurotic.——_Dose_,
6 to 12 gr.; in asthenic fevers, hysteria, hypochondriasis, impotency, &c.
Vanilla is reduced to powder (PULVIS VANILLÆ; POUDRE DE VANILLE) by
slicing it, and triturating the fragments with twice or thrice their
weight of well-dried lump sugar. For SUCRE DE VANILLE, 11 parts of sugar
are employed.
The following table given by Messrs Tieman and Harmann, in the _Journal of
the Berlin Chemical Society_, represents the quantities of Vanillin (the
aromatic principle of Vanilla) contained in that substance, as obtained
from different sources:——
Vanillin
per Cent.
Mexican Vanilla (1873, harvest) 1·69
Mexican Vanilla (1874, harvest) 1·86
Mexican Vanilla Medium quality 1·32
Bourbon, best quality (1874-75) 1·91
Bourbon, (1874-75) 1·97
Bourbon, (1874-75) 2·90
Bourbon, Small medium (1874-75) 1·55
Java, best quality (1873) 2·75
Java, best quality (1874) 1·56
=VANILLIN.= A crystallised substance obtained from pine juice by Messrs
Tiemann and Harmann. It has been shown to be identical with the aromatic
principle of Vanilla.
In a paper read before the Royal Society the authors have described the
process by which vanillin was artificially prepared by them. They state
that the sap of the cambium of coniferous trees contains a beautiful
crystalline glucoside coniferine, which was discovered by Kartig, and
examined some years ago by Rubel, who arrived at the formula
C_{24}H_{32}O_{12} + 3 Aq. A minute study of this compound leads us to
represent the molecule of coniferine by the expression, C_{16}H_{22}O_{3}
× 2 Aq., the per centages of which nearly coincide with the theoretical
values of Kubel’s formula.
Submitted to fermentation with emulsine, coniferine splits into sugar, and
a splendid compound, crystallising in prisms, which fuse at 73°. This body
is easily soluble in ether, less so in alcohol, almost insoluble in water;
its composition is represented by the formula C_{10}H_{12}O_{3}. The
change is represented by the equation——
C_{16}H_{22}O_{8} + H_{2}O = C_{6}H_{12}O_{6} + C_{10}H_{12}O_{3}.
Under the influence of oxidising agents, the product of fermentation
undergoes a remarkable metamorphosis. On boiling it with a mixture of
potassium bichromate and sulphuric acid, there passes with the vapour of
water in the first place ethylic aldehyd, and subsequently an acid
compound soluble in water, from which it may be removed by ether. On
evaporating the ethereal solution, crystals in stellar groups are left
behind, which fuse at 81°. These crystals have the taste and odour of
vanilla.
An accurate comparative examination has proved them to be identical with
the crystalline substance which constitutes the aroma of vanilla, and
which is often seen covering the surface of vanilla pods.
On analysis, the crystals we obtained were found to contain
C_{8}H_{8}O_{3}. This is exactly the composition which recent researches
of Carles have established for the aromatic principle of vanilla. The
transformation of the crystalline product of fermentation into vanillin is
represented by the following equation:
C_{10}H_{12}O_{3} + O = C_{2}H_{4}O + C_{8}H_{8}O_{3}.
To remove all doubt regarding the identity of artificial vanillin with the
natural compound, we have transformed the former into a series of salts,
which have the general formula, C_{8}H_{7}MO_{3}, and into two
substitution products, C_{8}H_{7}BrO_{31}, and C_{8}H_{7}TO_{3}, both of
which had previously been prepared by Carles from the natural compound.
=VAN SWIETEN’S SOLUTION.= Contains 1/1000th part of its weight of
corrosive sublimate; or 1/2 gr. per fl. oz.
=VAPOUR.= Vapours are really gases, and amenable to substantially the same
physical laws; as ordinarily understood, however, the difference between a
gas and a vapour is the following:——A gas is a form of matter which
exists, at ordinary temperatures and pressures, in a state of vapour;
whilst a vapour has been formed by the application of heat to a body
usually existing in the solid or liquid form; gases, therefore, differ
from vapours only in being derived from bodies which, in the solid or
liquid form, boil at very much lower temperatures.
=Vapour of Ammonia.= _Syn._ VAPOR AMMONIÆ. (St Th. Hosp.) Solution of
ammonia (·959), water, equal parts. A teaspoonful in a pint of water at
80° F. for each inhalation. In chronic laryngitis and functional aphonia.
=Vapour of Benzoin.= _Syn._ VAPOR BENZOINI. (St Th. Hosp.) Compound
tincture of benzoin, 1 oz. A teaspoonful to 1 pint of water at 140° F. In
acute inflammation of the pharynx and larynx.
=Vapour of Carbolic Acid.= _Syn._ VAPOR ACIDI CARBOLICI. (St Th. Hosp.)
Carbolic acid, 420 gr.; water, 1 dr.; 20 drops of this in 1 pint of water,
at 140° F., for each inhalation. For syphilitic and carcinomatous
ulcerations.
=Vapour of Chlorine.= _Syn._ VAPOR CHLORI. (B. P.) Put chlorinated lime, 2
oz., into a suitable apparatus, moisten it with cold water, and let the
vapour that arises be inhaled.
=Vapour of Conia.= _Syn._ VAPOR CONIÆ. (B. P.) Mix extract of hemlock, 60
gr.; solution of potash, 1 dr.; and distilled water, 9 dr. Put 20 minims
of the mixture on a sponge, in a suitable apparatus, that the vapour of
hot water passed over it may be inhaled.
=Vapour of Creosote.= _Syn._ VAPOR CREOSOTI. (B. P.) Mix creosote, 12
minims, and boiling water, 8 oz., in an apparatus so arranged that air may
be inhaled through the solution.
=Vapour of Hop.= _Syn._ VAPOR LUPULI. (St Th. Hosp.) Oil of hops, 6
minims; light carbonate of magnesia, 10 gr.; water, 1 oz. A teaspoonful in
1 pint of water, at 140° F., for each inhalation. Sedative.
=Vapour of Hydrocyanic Acid.= _Syn._ VAPOR ACIDI HYDROCYANICI. (B. P.) Mix
from 10 to 15 minims of diluted hydrocyanic acid with 1 dr. of cold water
in a suitable apparatus, and let the vapour that arises be inhaled.
=Vapour of Iodine.= _Syn._ VAPOR IODI. Mix tincture of iodine, 1 fl. dr.,
and water, 1 oz., and, having applied a gentle heat, let the vapour that
arises be inhaled.
=Vapour of Lactic Acid.= _Syn._ VAPOR ACIDI LACTICI. (St Th. Hosp.) Lactic
acid, 20 minims; distilled water, 1 oz.; mix. For spray inhalation.
Dissolves the membranous exudation in diphtheria,
=Vapour of Oil of Juniper.= _Syn._ VAPOR OLEI JUNIPERI. (St Th. Hosp.)
English oil of juniper, 20 minims; light carbonate of magnesia, 10 gr.;
water, 1 oz. A teaspoonful to 1 pint of water at 140° F. for each
inhalation. For vocal weakness.
=Vapour of Oil of Mountain Pine.= _Syn._ VAPOR PINI PLUMILIONIS. (St Th.
Hosp.) Oil of mountain pine, 1/2 dr.; light carbonate of magnesia, 15 gr.;
water, 1 oz.; 1 dr. to 1 pint of water at 140° F. for each inhalation. In
chronic laryngitis.
=Vapour of Oil of Myrtle.= _Syn._ VAPOR OLEI MYRTI. (St Th. Hosp.) Oil of
myrtle, 6 minims; light carbonate of magnesia, 6 gr.; water, 1 oz. A
teaspoonful in a pint of water at 140° F. for each inhalation. In acute
tonsillitis.
=Vapour of Nitrite of Amyl.= _Syn._ VAPOR AMYL NITRITIS. (St Th. Hosp.)
Nitrite of amyl, 8 minims; rectified spirit, 1 oz. A teaspoonful in a pint
of water at 100° F. for each inhalation. In asthma and spasm of the
glottis.
=Vapour of Scotch Pine.= _Syn._ VAPOR PINI SYLVESTRIS. Oil of Scotch pine
(fir-wood oil), 40 minims; light carbonate of magnesia, 20 gr.; water, 1
oz.; 1 dr. to 1 pint of water at 140° F. for each inhalation. In chronic
laryngitis.
=Vapour of Sulphurous Acid.= _Syn._ VAPOR ACIDI SULPHUROSI. (St Th. Hosp.)
Sulphurous acid, 15 minims; water, 1 oz. For spray inhalation. Stimulant
and antiseptic.
=Vapour of Thymol.= _Syn._ VAPOR THYMOLIS. Thymol, 6 gr.; rectified
spirit, 1 dr.; light carbonate of magnesia, 3 gr.; water, 1 oz. 1 dr. to 1
pint of water at 140° F. for each inhalation. In pharyngitis and
laryngitis when associated with exanthemata.
=VARICOSE VEINS.= See VARIX.
=VARIX.= The permanent unequal dilation of a vein or veins, which are then
said to be ‘varicose.’ It is known by the presence of a soft tumour, which
does not pulsate, and often assumes a serpentine figure. Varicose veins of
the groin and scrotum generally form a collection of knots. The treatment
consists of cold applications, and pressure from bandages. Some cases are
relieved by ligature. When occurring in the legs, much standing or walking
should be avoided, and the use of the elastic stockings made for the
purpose will be proper.
=VAR′NISH.= _Syn._ VERNIS, Fr. Any liquid matter, which, when applied to
the surface of a solid body, becomes dry, and forms a hard glossy
coating, impervious to air and moisture.
Varnishes are commonly divided into two classes——FAT or OIL VARNISHES and
SPIRIT VARNISHES. The fixed or volatile oils, or mixtures of them, are
used as vehicles or solvents in the former, and concentrated alcohol in
the latter.[254] The sp. gr. of alcohol for the purpose of making
varnishes should not be more than ·8156 (= 67 o. p.), and it should be
preferably chosen of even greater strength. A little camphor is often
dissolved in it, to increase its solvent power. The oil of turpentine,
which is the essential oil chiefly employed for varnishes, should be pure
and colourless. Pale drying linseed oil is the fixed oil generally used;
but poppy oil and nut oil are also occasionally employed. Among the
substances which are dissolved in the above menstrua are——amber, animé,
copal, elemi, lac, mastic, and sandarach, to impart body and lustre;
benzoin, on account of its agreeable odour; annotta, gamboge, saffron,
socotrine aloes, and turmeric, to give a yellow colour; dragon’s blood and
red sandal wood, to give a red tinge; asphaltum, to give a black colour
and body; and caoutchouc to impart toughness and elasticity.
[Footnote 254: Methylated spirit is now generally used for making spirit
varnishes, in place of duty-paid alcohol.]
In the preparation of spirit varnishes care should be taken to prevent the
evaporation of the alcohol as much as possible, and also to preserve the
portion that evaporates. On the large scale, a common still may be
advantageously employed; the head being furnished with a stuffing-box, to
permit of the passage of a vertical rod, connected with a stirrer at one
end and a working handle at the other. The gum and spirit being
introduced, the head of the still closely fitted on and luted, and the
connection made with a proper refrigerator, heat (preferably that of steam
or a water bath) should be applied, and the spirit brought to a gentle
boil, after which it should be partially withdrawn, and agitation
continued until the gum is dissolved. The spirit which has distilled over
should be then added to the varnish, and after thorough admixture the
whole should be run off, as rapidly as possible, through a silk-gauze
sieve, into stone jars, which should be immediately corked down, and set
aside to clarify. On the small scale, spirit varnishes are best made by
maceration in closed bottles or tin cans, either in the cold or by the
heat of a water bath. In order to prevent the agglutination of the resin,
it is often advantageously mixed with clean siliceous sand or pounded
glass, by which the surface is much increased, and the solvent power of
the menstruum greatly promoted.
To ensure the excellence of oil varnishes, one of the most important
points is the use of good drying oil. Linseed oil for this purpose should
be very pale, perfectly limpid or transparent, scarcely odorous, and
mellow and sweet to the taste.——100 galls. of such an oil is put into an
iron or copper boiler, capable of holding fully 150 galls., gradually
heated to a gentle simmer, and kept near that point for about 2 hours, to
expel moisture; the scum is then carefully removed, and 14 lbs. of finely
pulverised scale litharge, 12 lbs. of red lead, and 8 lbs. of powdered
umber (all carefully dried and free from moisture), are gradually
sprinkled in; the whole is then kept well stirred, to prevent the driers
sinking to the bottom, and the boiling is continued at a gentle heat for
about 3 hours longer; the fire is next withdrawn, and, after 30 to 40
hours’ repose, the scum is carefully removed, and the clear supernatant
oil decanted from the ‘bottoms,’——The product forms the best boiled or
drying oil of the varnish maker.——Another method is to heat a hogshead of
the oil gradually for 2 hours, then to gently simmer it for about 3 hours
longer, and, after removing the scum, to add, gradually, 1 lb. of the best
calcined magnesia, observing to mix it up well with the oil, and,
afterwards to continue the boiling pretty briskly for at least an hour,
with constant agitation. The fire is then allowed to die away, and, after
24 hours, the oil is decanted as before. The product is called ‘clarified
oil,’ and requires to be used with driers. It should be allowed to lay in
the cistern for 2 or 3 months to clarify.
In the preparation of oil varnishes, the gum is melted as rapidly as
possible, without discolouring or burning it; and when completely fused,
the oil, also heated to nearly the boiling point, is poured in, after
which the mixture is boiled until it appears perfectly homogeneous and
clear, like oil, when the heat is raised, the driers (if any are to be
used) gradually and cautiously sprinkled in, and the boiling continued,
with constant stirring, for 3 or 4 hours, or until a little, when cooled
on a palette knife, feels strong and stringy between the fingers. The
mixture is next allowed to cool considerably, but while still quite fluid,
the turpentine, previously made moderately hot, is cautiously added, and
the whole thoroughly incorporated. The varnish is then run through a
filter or sieve into stone jars, cans, or other vessels, and set aside to
clarify itself by subsidence. When no driers are used, the mixture of oil
and gum is boiled until it runs perfectly clear, when it is removed from
the fire, and, after it has cooled a little, the turpentine is added as
before.
It is generally conceived that the more perfectly the gum is fused, or
run, as it is called, the larger and stronger will be the product; and the
longer the boiling of the ‘gum’ and oil is continued, within moderation,
the freer the resulting varnish will work and cover. An excess of heat
renders the varnish stringy, and injures its flowing qualities. For pale
varnishes as little heat as possible should be employed throughout the
whole process. Good body varnishes should contain 1-1/2 lb.; carriage,
wainscot, and mahogany varnish, fully 1 lb.; and gold size and black
japan, fully 1/2 lb. of gum per gall., besides the asphaltum in the
latter. Spirit varnishes should contain about 2-1/2 lbs. of gum per gall.
The use of too much driers is found to injure the brilliancy and
transparency of the varnish. Copperas does not combine with varnish, but
only hardens it; sugar of lead, however, dissolves in it to a greater or
less extent. Boiling oil of turpentine combines very readily with melted
copal, and it is an improvement on the common process, to use it either
before or in conjunction with the oil, in the preparation of copal varnish
that it is desired should be very white. Gums of difficult solubility are
rendered more soluble by being exposed, in the state of powder, for some
time to the air.
Varnishes, like wines, improve by age; and should always be kept as long
as possible before use.
From the inflammable nature of the materials of which varnishes are
composed, their manufacture should be only carried on in some detached
building of little value, and built of uninflammable materials. When a pot
of varnish, gum, or turpentine catches fire, it is most readily
extinguished by closely covering it with a piece of stout woollen
carpeting, which should be always kept at hand, ready for the purpose.
An excellent paper, by Mr J. W. Niel, on the manufacture of varnishes,
will be found in the ‘Trans. of the Soc. of Arts,’ vol. xlix. See also the
articles ALCOHOL, AMBER, COPAL, OILS, &c., in this work.
=Varnish, Am′ber.= _Prep._ 1. Take of amber (clear and pale), 6 lbs.; fuse
it, add of hot clarified linseed oil, 2 galls.; boil until it ‘strings
well,’ then let it cool a little, and add of oil of turpentine 4 galls, or
q. s. Nearly as pale as copal varnish; it soon becomes very hard, and is
the most durable of the oil varnishes; but it requires some time before it
is fit for polishing, unless the articles are ‘stoved.’ When required to
dry and harden quicker, drying oil may be substituted for the linseed oil,
or ‘driers’ may be added during the boiling.
2. Amber, 4 oz.; pale boiled oil, 1 quart; proceed as last. Very hard.
3. Pale transparent amber, 5 oz.; clarified linseed oil or pale boiled
oil, and oil of turpentine, of each 1 pint; as before.
_Obs._ Amber varnish is suited for all purposes where a very hard and
durable oil varnish is required. The paler kind is superior to copal
varnish, and is often mixed with the latter to increase its hardness and
durability. The only objection to it is the difficulty of preparing it of
a very pale colour. It may, however, be easily bleached with some
fresh-slaked lime.
=Varnish, Balloon.= See VARNISH, FLEXIBLE (_below_).
=Varnish, Bessemer’s.= This consists of a pale oil copal varnish, diluted
with about 6 times its volume of oil of turpentine, the mixture being
subsequently agitated with about 1-30th part of dry slaked lime, and
decanted after a few days’ repose. Five parts of the product mixed with 4
parts of bronze powder forms ‘Bessemer’s gold paint.’
=Varnish, Black.= _Prep._ 1. (BLACK AMBER VARNISH.) From amber, 1 lb.;
fuse, add, of hot drying oil, 1/2 pint; powdered black resin, 3 oz.;
asphaltum (Naples), 4 oz.; when properly incorporated and considerably
cooled, add of oil of turpentine, 1 pint. This is the beautiful black
varnish of the coachmakers.
2. (IRONWORK BLACK.) From asphaltum, 48 lbs.; fuse, add of boiled oil, 10
galls.; red lead and litharge, of each 7 lbs.; dried and powdered white
copperas, 3 lbs.; boil for 2 hours, then add of dark gum amber (fused), 8
lbs.; hot linseed oil, 2 galls.; boil for 2 hours longer, or until a
little of the mass, when cooled, may be rolled into pills, then withdraw
the heat, and afterwards thin it down with oil of turpentine, 30 galls.
Used for the ironwork of carriages, and other nice purposes.
(3. BLACK JAPAN, BITUMINOUS VARNISH.)——_a._ From Naples asphaltum, 50
lbs.; dark gum animé, 8 lbs.; fuse, add of linseed oil, 12 galls.; boil as
before, then add of dark gum amber, 10 lb., previously fused and boiled
with linseed oil, 2 galls.; next add of driers q. s., and further proceed
as ordered in No. 2. Excellent for either wood or metals.
_b._ From burnt umber, 8 oz.; true asphaltum, 4 oz.; boiled linseed oil, 1
gall.; grind the umber with a little of the oil; add it to the asphaltum,
previously dissolved in a small quantity of the oil by heat; mix, add the
remainder of the oil, boil, cool, and thin with a sufficient quantity of
oil of turpentine. Flexible.
4. (BRUNSWICK BLACK.)——_a._ To asphalt, 2 lbs., fused in an iron pot, add
of hot boiled oil, 1 pint; mix well, remove the pot from the fire, and,
when cooled a little, add of oil of turpentine, 2 quarts. Used to blacken
and polish grates and ironwork. Some makers add driers.
_b._ From black pitch and gas-tar asphaltum, of each 25 lbs.; boil gently
for 5 hours, then add, of linseed oil, 8 galls.; litharge and red lead, of
each 10 lbs.; boil as before, and thin with oil of turpentine, 20 galls.
Inferior to the last, but cheaper.
=Varnish, Body.= _Prep._ 1. From the finest African copal, 8 lbs.; drying
oil, 2 galls.; oil of turpentine, 3-1/2 galls.; proceed as for AMBER
VARNISH. Very hard and durable.
2. Pale gum copal, 8 lbs.; clarified oil, 2 galls.; dried sugar of lead,
1/2 lb.; oil of turpentine, 3-1/2 galls.; proceed as before, and mix the
product, whilst still hot, with the following varnish:——Pale gum animé, 8
lbs.; linseed oil, 2 galls.; dried white copperas, 1/4 lb.; oil of
turpentine, 3-1/2 galls.; the mixed varnishes are to be immediately
strained into the cans or cistern. Dries in about 6 hours in winter, and
in about 4 hours in summer. Used for the bodies of coaches and other
vehicles.
=Varnish, Bookbinder’s.= _Prep._ Take of pale gum sandarach, 3 oz.;
rectified spirit, 1 pint; dissolve by cold digestion and frequent
agitation. Used by binders to varnish morocco leather book-covers. A
similar varnish is also prepared from very pale shell-lac and wood
naphtha.
=Varnish for Boots and Shoes.= See BOOTS and SHOES.
=Varnish, Cabinet-maker’s.= French polish is occasionally so called.
=Varnish, Carriage.= _Prep._ 1. (SPIRIT.) Take of gum sandarach, 1-1/4
lb.; very pale shell-lac, 3/4 lb.; very pale transparent resin, 1/2 lb.;
rectified spirit of ·8221 (64 o. p.), 3 quarts; dissolve, and add of pure
Canadian balsam, 1-1/2 lb. Used for the internal parts of carriages, &c.
Dries in 10 minutes or less.
2. (OIL.)——_a._ (Best pale.) Take of pale African copal, 8 lbs.; fuse, add
of clarified linseed oil, 2-1/2 galls.; boil until very stringy, then add
of dried copperas and litharge, of each 1/4 lb.; again boil, thin with oil
of turpentine, 5-1/2 galls.; mix, whilst both are hot with the following
varnish, and immediately strain the mixture into a covered vessel:——Gum
animé, 8 lbs.; clarified linseed oil, 2-1/2 galls.; dried sugar of lead
and litharge, of each 1/4 lb.; boil as before, thin with oil of
turpentine, 5-1/2 galls. Dries in 4 hours in summer, and 6 in winter. Used
for the wheels, springs, and carriage parts of coaches, and other
vehicles, and by house painters, decorators, &c., who want a strong,
quick-drying, and durable varnish.
_b._ (Second quality.) From gum animé (‘sorts’), 8 lbs.; clarified oil, 3
galls.; litharge, 5 oz.; dried and powdered sugar of lead and white
copperas, of each 4 oz.; boil as last, and thin with oil of turpentine,
5-1/2 galls. Used as the last.
=Varnish, Chinese.= _Prep._ From mastic and sandarach, of each 2 oz.;
rectified spirit (64 o. p.), 1 pint; dissolve. Dries in 6 minutes. Very
tough and brilliant.
=Varnish, Copal.= _Prep._ 1. (OIL.)——_a._ From pale hard copal, 2 lbs.;
fuse, add of hot drying oil, 1 pint; boil as before directed, and thin
with oil of turpentine, 3 pints, or q. s. Dries hard in 12 to 24 hours.
_b._ From clear and pale African copal, 8 lbs.; pale drying oil, 2 galls.;
rectified oil of turpentine, 3 galls.; proceed as before and immediately
strain it into the store can or cistern. Very fine, hard, and durable.
2. (SPIRIT.)——_a._ From coarsely powdered copal and glass, of each 4 oz.;
alcohol of 90% (64 o. p.), 1 pint; camphor, 1/2 oz.; heat the mixture,
with frequent stirring, in a water bath, so that the bubbles may be
counted as they rise until solution is complete, and, when cold, decant
the clear portion.
_b._ From copal (which has been melted, dropped into water, and then dried
and powdered), 4 oz.; gum sandarach, 6 oz.; mastic, 2 oz.; pure Chio
turpentine, 3 oz.; powdered glass, 5 oz.; spirit of 90%, 1 quart; dissolve
by a gentle heat. Dries rapidly.
3. (TURPENTINE.) To oil of turpentine, 1 pint, heated in a water bath, add
in small portions at a time, of powdered copal (prepared as above), 3 to 4
oz.; dissolve, &c., as before. Dries slowly, but is very pale and durable.
4. (JAPANNER’S COPAL VARNISH.) From pale African copal, 7 lbs.; pale
drying oil, 1/2 gall.; oil of turpentine, 3 galls.; proceed as in No. 1.
Dries in 20 to 60 minutes, and may be polished as soon as hard,
particularly if stoved. See JAPANNING.
_Obs._ All copal varnishes, when properly made, are very hard and durable,
though less so than those of amber; but they have the advantage over the
latter of being paler. They are applied on coaches, pictures, polished
metal, wood, and other objects requiring a good durable varnish. Animé is
frequently substituted for copal in the copal varnishes of the shops. See
VARNISHES, BODY, CARRIAGE, and COPAL, &c.
=Varnish, Crystal.= _Prep._ 1. From genuine pale Canada balsam and
rectified oil of turpentine, equal parts. Used for maps, prints, drawings,
and other articles of paper, and also to prepare tracing paper, and to
transfer engravings.
2. Mastic, 3 oz.; rectified spirit, 1 pint; dissolve. Used to fix pencil
drawings.
=Varnish, Drying.= Spirit copal varnish.
=Varnish, Dutch.= Lac and toy varnishes are often so called.
=Varnish, Etch′ing.= See ETCHING.
=Varnish, Fat.= See OIL VARNISH.
=Varnish, Flexible.= _Syn._ BALLOON VARNISH, CAOUTCHOUC V., INDIA-RUBBER
V. _Prep._ 1. From india rubber (cut small), 1-1/2 oz.; chloroform, ether
(washed), or bisulphuret of carbon, 1 pint; digest in the cold until
solution is complete. Dries as soon as it is laid on. Pure gutta percha
may be substituted for india rubber.
2. India rubber, in shavings, 1 oz.; rectified mineral naphtha or benzol.
1 pint; digest at a gentle heat in a closed vessel, and strain. Dries very
badly, and never gets perfectly hard.
3. India rubber, 1 oz.; drying oil, 1 quart; dissolve by heat. Very tough;
dries in about 48 hours.
4. Linseed oil, 1 gall.; dried white copperas and sugar of lead, of each 3
oz.; litharge, 8 oz.; boil, with constant agitation, until it strings
well, then cool slowly, and decant the clear portion. If too thick, thin
it down with quick-drying linseed oil. The above are used for balloons,
gas bags, &c. See BALLOON, CAOUTCHOUC, &c.
=Varnish, Furniture.= A solution of pure white wax, 1 part, in rectified
oil of turpentine, 4 parts, frequently passes under this name. See
VARNISHES, BODY, CARRIAGE, and COPAL, &c.
=Varnish, Gilder’s.= _Prep._ (Watin.) Pale gum-lac in grains, gamboge,
dragon’s blood, and annotta, of each 12-1/2 oz.; saffron, 3-1/4 oz.;
dissolve each resin separately in 5 pints of alcohol of 90%, and make two
separate tinctures of the dragon’s blood and annotta, with a like quantity
of spirit; then mix the solutions in the proper proportions to produce the
required shade. Used for gilded articles, &c.
=Varnish, Glass.= A solution of soluble glass. Used to render wood, &c.,
fire-proof.
=Varnish, Gun-barrel.= _Prep._ From shell-lac, 1-1/2 oz.; dragon’s blood,
3 dr.; rectified spirit, 1 quart. Applied after the barrels are ‘browned.’
=Varnish, Hair.= _Prep._ From hog’s bristles (chopped small), 1 part;
drying oil, 10 parts; dissolve by heat. Said to be used to give cotton or
linen cloth the appearance of horse-hair.
=Varnish, India-rubber.= VARNISH. See FLEXIBLE (_above_).
=Varnish, Italian.= _Prep._ Boil Scio turpentine until brittle, powder it,
and dissolve this in oil of turpentine. Used for prints, &c.
=Varnish, Japan.= Pale amber or copal varnish. Used for japanning tin,
papier mâché, &c.
=Varnish, Lac.= _Prep._ 1. Pale seed-lac (or shell-lac), 8 oz.; rectified
spirit, 1 quart; dissolve.
2. Substitute lac bleached with chlorine for seed-lac. Both are very
tough, hard, and durable, but quite inflexible. Wood naphtha may be
substituted for spirit. Used for pictures, metal, wood, or leather, and
particularly for toys.
=Varnish, Lac (Aqueous).= _Prep._ From pale shell-lac, 5 oz.; borax, 1
oz.; water, 1 pint; digest at nearly the boiling point until dissolved;
then strain. Equal to the more costly spirit varnish for many purposes; it
is an excellent vehicle for water colours, inks, &c.; when dry, it is
waterproof.
=Varnish, Lac (Coloured).= _Syn._ LACQUER, BRASSWORK VARNISH. _Prep._ 1.
Take of turmeric (ground), 1 lb.; rectified spirit, 2 galls.; macerate for
a week, strain, with expression, and add to the tincture, gamboge, 1-1/2
oz.; pale shell-lac, 3/4 lb.; gum sandarach, 3-1/2 lbs.; when dissolved,
strain, and further add of good turpentine varnish, 1 quart. Gold
coloured.
2. Seed-lac, 3 oz.; turmeric, 1 oz.; dragon’s blood, 1/4 oz.; rectified
spirit, 1 pint; digest for a week, frequently shaking, then decant the
clear portion. Deep gold coloured.
3. Spanish annotta, 3 lbs.; dragon’s blood, 1 lb.; gum sandarach, 3-1/4
lbs.; rectified spirit, 2 galls.; turpentine varnish, 1 quart; as before.
Red coloured.
4. Gamboge, 1 oz.; Cape aloes, 3 oz.; pale shell-lac, 1 lb.; rectified
spirit, 2 galls.; as before. Pale brass coloured.
5. Seed-lac, dragon’s blood, annotta, and gamboge, of each 1/4 lb.; gum
sandarach, 2 oz.; saffron, 1 oz.; rectified spirit, 1 gall. Resembles the
last.
_Obs._ Lacquers are used upon polished metals and wood, to impart to them
the appearance of gold. Articles in brass, tin plate, and pewter, or which
are covered with tinfoil, are more especially so treated. As lacquers are
required of different depths and shades of colour, it is best to keep a
concentrated solution of each of the colouring ingredients ready, so that
it may be added, at any time, to produce any desired tint.
=Varnish, Mahogany.= _Prep._ From gum animé (‘sorts’), 8 lbs.; clarified
oil, 3 galls.; litharge and powdered dried sugar of lead, of each 1/4 lb.;
proceed as for body varnish, and thin with oil of turpentine, 5 galls., or
q. s.
=Varnish, Mastic.= _Syn._ PICTURE VARNISH, TURPENTINE V., TINGRY’S ESSENCE
V. _Prep._ 1. Take of pale and picked gum mastic, 5 lbs.; glass (pounded
as small as barley, and well Washed and dried), 3 lbs.; finest newly
rectified oil of turpentine (lukewarm), 2 galls.; put them into a clean
4-gall. tin bottle or can, bung down securely, and keep rolling it
backwards and forwards pretty smartly on a counter, or any other solid
place, for at least 4 hours, when, if the gum is all dissolved, the
varnish may be decanted, strained through muslin into another bottle, and
allowed to settle; if the solution is still incomplete, the agitation must
be continued for some time longer, or the gentle warmth applied as well.
Very fine.
2. (Second quality.) From mastic, 4 lbs.; oil of turpentine, 2 galls.;
dissolve with heat.
_Obs._ Mastic varnish is much used for pictures, &c.; when good, it is
tough, hard, brilliant, and colourless. It greatly improves by age, and,
when possible, should never be used before it has been made at least a
twelve-month. Should it get ‘chilled,’ 1 lb. of well-washed siliceous sand
should be made moderately hot and added to each gallon, which must then be
well agitated for 5 minutes, and afterwards allowed to settle.
=Varnish, Oak.= _Syn._ WAINSCOT VARNISH, COMMON TURPENTINE V. _Prep._ 1.
Clear pale resin, 3-1/2 lbs.; oil of turpentine, 1 gall.; dissolve.
2. To the last add of Canada balsam, 1 pint, Both are cheap and excellent
common varnishes for wood or metal.
=Varnish, Oil.= The finer qualities are noticed under AMBER, BODY,
CARRIAGE, and COPAL VARNISH; the following produces the ordinary oil
varnish of the shops:——Take of good clear resin, 3 lbs.; drying oil, 1/2
gall.; melt, and thin with oil of turpentine, 2 quarts. A good and durable
varnish for common work.
=Varnish, Painter’s.= See CARRIAGE, COPAL, MAHOGANY, OAK, OIL, and other
varnishes; the selection depending greatly on the colour and quality of
the work.
=Varnish, Patent Leather.= This is carefully prepared drying oil. The
skins being stretched on a board, and every trace of grease being removed
from them by means of a mixture of fullers earth and water, they are ready
to receive the varnish, which is then spread upon them, very thinly, by
means of a species of scraper. The first coat varnish consists of pale
Prussian blue (that containing some alumina), 5 oz.; drying oil, 1 gall.;
boiled to the consistence of single size, and, when cold, ground with a
little vegetable black; it is stoved and afterwards polished with
fine-grained pumice——the second coating resembles the first, excepting in
having a little pure Prussian blue mixed with it;——the third coat varnish
consists of a similar mixture, but the oil is boiled until it strings
well, and a little more pure Prussian blue and vegetable black are
added;——the last coat varnish, or finish, is the same as the third, but
must contain 1/2 lb. of pure dark-coloured Prussian blue, and 1/4 lb. of
pure vegetable black per gall., to which a little oil copal or amber
varnish is often added; each coat being duly stoved and pumiced before the
next is applied. The heat of the stove or oven is commonly 120° Fahr. for
‘enamelled skins,’ as those of the calf and seal, intended for ‘uppers,’
and 175° to 180° for stout ‘japan leather,’ the exposure in the stove is
commonly for 6 to 10 hours. The skins are next oiled and grained. The
‘graining’ of the ‘enamelled skins’ is done by holding the skin in one
hand, and with a curved board lined with cork (graining stick), lightly
pressed upon the fleshy side, working it up and down until the proper
effect is produced.
=Varnish, Picture.= Several varnishes, especially mastic varnish, are
called by this name. Pale copal or mastic varnish is generally used for
oil paintings, and crystal, white hard spirit, or mastic varnish, for
water-coloured drawings on paper.
=Varnish, Printer’s.= Diluted with twice its volume of oil of turpentine,
it forms a good common varnish.
=Varnish, Sealing-wax.= Black, red, or any coloured sealing-wax, broken
small, with enough rectified spirit (or methylated spirit) to cover it,
digested till dissolved. A most useful varnish for wood-work of electrical
or chemical apparatus, for tops of corks, &c.
=Varnish, Spirit.= _Prep._ 1. (BROWN HARD.)——_a._ From gum sandarach, 3
lbs.; pale seed-lac or shell-lac, 2 lbs.; rectified spirit (65 o. p.), 2
galls.; dissolve, and add of turpentine varnish, 1 quart; agitate well,
strain (quickly) through gauze, and in a month decant the clear portion
from the sediment. Very fine.
_b._ From seed-lac and yellow resin, of each 1-1/2 lb.; rectified spirit,
5 quarts; oil of turpentine, 1-1/4 pint; dissolve. Inferior to the last.
2. (WHITE HARD.)——_a._ From gum sandarach (picked), 5 lbs.; camphor, 2
oz.; washed and dried coarsely pounded glass, 3 lbs.; rectified spirit (65
o. p.), 7 quarts; proceed as in making mastic varnish; when strained, add
of pure Canada balsam, 1 quart. Very pale, durable, and brilliant.
_b._ From gum sandarach and gum mastic, of each, picked, 4 oz.; coarsely
powdered glass, 8 oz.; rectified spirit, 1 quart; dissolve, and add of
pure Strasburg turpentine, 3 oz. Very fine.
3. (SOFT BRILLIANT.) From sandarach, 6 oz.; elemi (genuine), 4 oz.; animé,
1 oz.; camphor, 1/2 oz.; rectified spirit, 1 quart; as before.
4. (SCENTED.) To the preceding add some gum benzoin, balsam of Peru,
balsam of Tola, oil of lavender, or the essence of musk or ambergris. The
first two can only be employed for dark varnishes.
_Obs._ The above varnishes are chiefly applied to articles of the
toilette, as work-boxes, card-cases, &c.; but are also suitable to other
articles, whether of paper, wood, linen, or metal, that require a
brilliant and quick-drying varnish. They dry almost as soon as applied,
and are usually hard enough to polish in 24 hours. They are, however, much
less durable, and more liable to crack, than oil varnishes.
=Varnish, Stopping-out.= _Syn._ PETIT VERNIS, Fr. From lampblack, made
into a paste with turpentine. Used by engravers. See ETCHING.
=Varnish, Tingry’s.= MASTIC VARNISH.
=Varnish, Toy.= Similar to common spirit varnish, but using carefully
rectified wood naphtha as the solvent. See VARNISHES, LAC and SPIRIT.
=Varnish, Transfer.= _Syn._ MORDANT VARNISH. _Prep._ From mastic (in
tears) and sandarach, of each 4 oz.; rectified spirit, 1-1/2 pint;
dissolve, and add of pure Canada balsam, 1/2 pint. Used for transferring
and fixing engravings or lithographs on wood, and for gilding, silvering,
&c. See VARNISH, CRYSTAL.
=Varnish, Turpentine.= See VARNISHES, MASTIC, and OAK.
=Varnish, Wainscot.= See VARNISH, OAK.
=Varnish, Wax.= _Syn._ MILK OF WAX; EMULSIO CERÆ SPIRITUOSA, L. _Prep._ 1.
Take of white wax (pure), 1 lb.; melt it with as gentle a heat as
possible, add of warm rectified spirit, sp. gr. ·830 (60 o. p.), 1 pint;
mix perfectly, and pour the liquid out upon a cold porphyry slab; next
grind it with a muller to a perfectly smooth paste, adding more spirit as
required; put the paste into a marble mortar, make an emulsion with water,
3-1/2 pints, gradually added, and strain it through muslin. Used as a
varnish for paintings; when dry, a hot iron is passed over it, or heat is
otherwise evenly applied, so as to fuse it, and render it transparent,
after which, when quite cold, it is polished with a clean linen cloth.
The most protective of all varnishes.
2. Wax (pure), 5 oz.; oil of turpentine, 1 quart; dissolve. Used for
furniture. See VARNISH, SEALING-WAX.
=Varnish, White.= See VARNISH, SPIRIT, 2, _a_ and _b_.
=VAR′NISHING.= To give the highest degree of lustre to varnish after it is
laid on, as well as to remove the marks of the brush, it undergoes the
operation of polishing. This is performed by first rubbing it with very
finely powdered pumice stone and water, and afterwards with an oiled rag
and tripoli, until the required polish is produced. The surface is, last
of all, cleaned with soft linen cloths, cleared of all greasiness with
powdered starch, and then rubbed bright with the palm of the hand.
In varnishing great care must be taken that the surface is free from
grease or smoke; as, unless this be the case, the best oil or turpentine
varnish in the world will not dry and harden. Old articles are usually
washed with soap and water, by the painters, before being varnished, to
prevent any misadventure of the kind alluded to.
=VASELINE.= See COSMOLINE.
=VEAL.= “The grain should be close, firm, and white, and the fat of a
pinkish white, not a dead white, and the kidneys well covered with a thick
white fat.” (Soyer.)
Veal, like pork, requires to be well dressed, to develop its nutritive
qualities. It should also be eaten fresh, as a peculiar principle is
generated in it when improperly kept, which acts as a malignant poison.
See ROASTING, &c.
=VEG′ETABLE AL′KALI†.= Potassa.
=VEGETABLE JUICES.= See _below_.
=VEGETABLES.= Vegetables are organic beings, which are distinguished from
animals by a number of characteristics, but, like them, are composed of
certain proximate principles, or compounds, which possess a high degree of
scientific interest, and in many cases are invaluable to man. Among the
most important of these are——albumen, gluten, gum, lignin, starch, sugar,
tannin, wax, the fixed and volatile oils, the resins, and gum-resins, the
alkaloids, and innumerable forms of extractive matter. Several of these
substances are noticed under their respective names.
The method of propagating plants from their seeds, depending on their
simple exposure, at the proper season, to warmth and moisture, under the
protection of the soil, is well known; that by propagation from ‘slips’
and ‘cuttings,’ which will doubtless prove interesting to the amateur
gardener, are noticed below.
The choice of slips and cuttings should be made from the side shoots of
trees and plants, and, when possible, from such as recline towards the
grounds, observing, when they are removed by the knife, to leave a little
wood of a former year or season’s growth attached to them, as such are
found to take root more readily than when they are wholly composed of new
wood. The time to take slips or cuttings is as soon as the sap gets into
full motion. Before setting them the latter should be cut across, just
below an eye or joint, with as smooth a section as possible, observing not
to injure the bud. The superfluous leaves may be removed, but a sufficient
number should be left on for the purposes of vegetation. The common
practice of removing all or nearly all the leaves of cuttings is
injudicious. In some cases leaves alone will strike root. When cuttings
are set in pots, they should be so placed as to reach to the bottom and
touch the sides throughout their whole length, when they will seldom fail
to become rooted plants. In the case of tubular-stalked plants it is said
to be advantageous to insert both ends into the soil, each of which will
take root, and may then be divided, when two plants will be produced
instead of one. An equable temperature, a moist atmosphere, a shady
situation, and a moderate supply of water, are the principal requisites to
induce speedy rooting. Excess of any of these is prejudicial. When the
size of the cuttings admit, it is better to place them under a hand- or
bell-glass, which will preserve a constant degree of heat, and prevent
evaporation from the surface of the leaves, which is the most common cause
of their dying, especially in hot, dry weather.
_Qual._ The vegetable kingdom furnishes by far the larger portion of the
food of man, and indirectly, perhaps, the whole of it. The great value of
culinary vegetables and fruit in a mixed diet need not be insisted on,
since it is a fact which is almost universally known and appreciated.
In the choice of culinary vegetables observe, that if they are stiff and
break freely and crisply, they are fresh, and fit for food; if, on the
contrary, they have a flabby appearance, or are soft or discoloured, they
are stale, and should be rejected.
The dose of the generality of vegetable substances that exercise no very
marked action on the human frame is about 1/2 to 1 dr. of the powder,
night and morning; or 1 oz., or q. s. to impart a moderately strong colour
or taste, may be infused or boiled in 1 pint of water, and a wine-glassful
or thereabouts taken 2 or 3 times a day.
_Collection and Pres._ The following general directions are given in the
London Pharmacopœia for the collection and preservation of vegetable
substances——(vegetabilia, Ph. L.):——
“Vegetables are to be collected in dry weather, and when neither wet with
rain nor dew; they are to be collected annually, and are not to be kept
beyond a year.
“Barks are to be collected at that season in which they can be most easily
separated from the wood.” Spring is the season here alluded to; as at this
time, after the sap begins to ascend, the bark is, in general, very
easily separated.
“Flowers are to be collected recently blown.” The red rose, however, must
be gathered before the buds are expanded.
“Fruits and seeds are to be collected when ripe.
“Herbs and leaves are to be gathered after the flowers have expanded, and
before the seeds are mature.
“Roots and rhizomes (underground stems), for the most part, are to be dug
up after the old leaves and stalks have fallen, and before the new ones
appear.” (“Roots, which are required to be preserved fresh, should be
buried in dry sand.”——Ph. L. 1836.)
“Seeds are to be collected when they are ripe, and before they drop from
the plant.” (“They ought to be preserved in their seed vessels.”——Ph. L.
1836.)
“The different parts of vegetables are to be kept dried for use, except
where we shall otherwise direct. Expose those you wish to dry, within a
short time after they have been gathered, in shallow wicker baskets, to a
gentle heat, in a dark place, and where there is a current of air. Then,
the moisture being driven off, gradually increase the heat to 150° Fahr.,
in order that they may be dried. Finally, preserve the more delicate
parts, viz. flowers and leaves, in black glass vessels, well closed, and
keep the rest in proper vessels, preventing the access of light and
moisture.”
Fruits, culinary vegetables, and vegetable juice, of every class, may be
preserved for any length of time by several of the methods described under
PUTREFACTION. On the small scale the following method is often
adopted:——The substances to be preserved are put into strong glass or
stoneware bottles, with necks of a proper size, which are then corked with
the greatest care, tied or wired, and lined with a mixture of lime and
soft cheese, or with a paste formed of linseed meal and water, spread on
rags; or tin cases are employed, and are soldered up instead of being
corked. The bottles are then placed in an oven, the temperature of which
is cautiously raised to fully 212° Fahr.; or they are enclosed,
separately, in canvas bags, and put into a copper of water to which some
salt has been added, which is then gradually heated until it boils, and
thus kept for 15 or 20 minutes; the whole is next left to cool, when the
bottles are taken out and carefully examined before being laid by, lest
they should have cracked or the lute have given way.
Herbs and flowers are now generally preserved for distillation by means of
common salt. The objection which is raised against the use of fresh
aromatic plants is thus obviated, whilst the odours of the distilled
products are rendered superior to those obtained from either the recent or
dried plant, fruit, or flower, without the great loss, inconvenience, or
trouble attending the common methods. Besides, many aromatic and odorous
substances almost entirely lose their properties by drying; while most of
them yield more oil, and that of a finer quality, in the fresh than in the
dried state. The odours of roses, elder flowers, and a variety of others
are vastly improved by this treatment, and these flowers may thus be
preserved with ease and safety from season to season, or even longer, if
required. The process simply consists in intimately mixing the flowers or
other vegetables, soon after being gathered, with about 1/4 their weight,
or less, of good dry salt, and ramming down the mixture as tightly as
possible in strong casks. The casks are then placed in a cold cellar, and
covered with boards, on which heavy weights are put, to keep the mass
tight and close. See FRUITS, PUTREFACTION, &c.
=Vegetables, Juices of.= 1. (EXPRESSED VEGETABLE JUICE, SIMPLE V. J.;
SUCCI EXPRESSI, L.) These are obtained by bruising the fresh leaves, or
other vegetable matter, in a marble mortar, or in a mill, and expressing
the liquid portion by means of a powerful screw press. After defecation
for 12 or 14 hours in a cold situation, the juice is either decanted or
filtered from the feculous sediment, and is next heated for some minutes
to about 185° Fahr., to coagulate albuminous matter. The clear portion is
subsequently separated as before, and the product preserved for use in
well-closed and well-filled bottles, in a cool situation. Some plants, as
borage, cabbage, &c., require the addition of 1/8 of water before being
pressed. The expression of the juice of lemons, oranges, quinces, &c., is
facilitated by previously mixing the pulp with clean chopped straw.
Buckthorn berries, mulberries, &c., after being crushed between the hands,
are commonly left for 3 or 4 days to undergo a slight fermentation before
pressing them.
The expression of the juices of the narcotic plants, and of some other
vegetables, has lately assumed considerable interest, from these juices
being now extensively used in pharmacy for the preparation of extracts and
the preserved juices, noticed below. It appears that the juice of young
plants just coming into flower yield only 2/3 the amount of extract which
may be obtained from the same quantity of juice expressed from the matured
plant, or when the flowers are fully blown, and the strength of the
product is also inferior; the case appears to be best met by selecting the
plants when more than half the flowers are fully blown. The leaves alone
should be preferably employed, and should be exclusively of the second
year’s growth, when the plants are biennials. (Squire.) The homœopathists
commonly employ the whole flowering herb.
The INSPISSATED VEGETABLE JUICES (SUCCUS SPISSATIS) are now included among
the extracts.
The principal simple vegetable juices of commerce are——
BUCKTHORN JUICE (SUCCUS RHAMNI——Ph. L.), from the fruit of _Rhamnus
catharticus_, or buckthorn berries.
CITRON JUICE (SUCCUS CITRI), chiefly imported from Italy in large casks.
LEMON JUICE (SUCCUS LIMONUM), Ph. L. from lemons that spoil before they
can be sold; also imported.
MULBERRY JUICE (SUCCUS MORI——Ph. L.), from the fruit of the mulberry.
ORANGE JUICE (SUCCUS AURANTII), obtained from the same source as that of
lemons.
CONCENTRATED ORANGE JUICE (SUCCUS SPISSATIS AURANTII vel AURANTIORUM) and
CONCENTRATED LEMON JUICE (SUCCUS SPISSATUS LIMONUM) are prepared by
evaporating the fresh juices of oranges and lemons, either alone or mixed
with sugar, and are employed as substitutes for the fruit, where the
latter cannot be obtained.
2. (ALCOHOLISED VEGETABLE JUICES, PRESERVED V. J.; TINCTURES OF RECENT
PLANTS; SUCCI ALCOHOLATI, L.; ALCOOLATURES, Fr.) _Prep._ _a._ The juice,
obtained by powerful pressure, in the manner noticed above, is allowed to
remain for 24 hours in a cold place, when the clear portion is decanted
from the feculous matter which has subsided, and is then agitated with one
half its volume of rectified spirit (56 o. p.); after another 24 hours the
clear portion is again decanted and, if necessary, filtered through
bibulous paper or linen. In this way are now generally prepared the
preserved juices of aconite, belladonna, colchicum (corms), hemlock,
henbane, foxglove, elaterium, lactuca virosa, taraxacum, &c., sold in this
country.
_b._ (P. Cod.) To the fresh leaves, bruised in a marble mortar, is added
an equal weight of rectified spirit, and after maceration for 15 days the
whole is pressed, and the resulting tincture filtered. In this manner are
prepared tinctures of the fresh leaves of aconite (tinctura aconiti cum
foliis recentibus), belladonna, foxglove, hemlock, henbane, strong-scented
lettuce (_Lactuca virosa_), stramonium, trailing poison oak (_Rhus
toxicodendron_), mugwort (_Artemisia vulgaris_), colchicum (corms),
squirting cucumber, white poppy, taraxacum, &c., of the Paris Codex.
_Obs._ These tinctures are much more powerful, and more certain in their
operation, than those prepared from the dried plants. The commencing dose
is from 2 to 5 drops, the effects of which should be carefully watched.
The products of the first of the above formulæ keep as well as the
ordinary tinctures, and there is less waste of spirit than with the
second. That of the P. Cod. is, however, preferred by M. Soubeiran, as
affording more uniform products; an opinion which is questionable. Béral
orders equal weights of juice and spirit; Mr Squire recommends 1/2 part;
Messrs Bentley & Davenport 1/4 part (both by volume), and Mr Gieseke only
1/5 part (by weight), of spirit to 1 part of the expressed juice. The
homœopathists generally go with M. Béral. “Our own experience, which has
been very considerable, and extends over upwards of 16 years, leads us to
prefer the proportions given in formula _a_, which are similar to those of
Mr Squire. If less spirit be employed, the product is apt to suffer rapid
deterioration when kept in a warm shop or surgery.” (Cooley.)
3. (ETHERIZED VEGETABLE JUICES; SUCCI ÆTHERIZATI,——L.; ETHÉROLATURES, SUCS
ÉTHÉRES, Fr.) For these we are indebted to M. Bouchardat. They are
prepared as follows: Ether is gradually added to the depurated freshly
expressed juice, until, after active agitation, a thin layer of it rises
to the surface on the mixture being allowed to repose for a minute or two;
the whole is then set aside for 24 hours, when the supernatant ether is
expertly removed by means of a pipette or syringe, and the juice is
filtered; lastly, the decanted ether is returned to the filtrate, and the
etherised juice is at once put into well-stoppered bottles. For use, one
of the bottles is reversed, and the dose taken from the lower part, so
that the ether remains behind. We find, in practice, that decantation,
carefully conducted, may be substituted for filtration; thus not only
rendering the process less costly, but ensuring a more uniform product.
The etherised juices are said to retain their active properties for an
indefinite period. The method has been successfully applied to the juices
of aconite, anemone, black hellebore, and hemlock, and is probably
applicable to many others; but, we think, not to the juices of all the
narcotic plants, as has been asserted.
=Vegetable Fibres.= The following method for the identification of
vegetable fibres is intended to supplement the information previously
given on this subject. Its originator, M. Vetillard, applies it for
distinguishing the fibres of linen, hemp, cotton, jute, China grass, and
New Zealand flax. The following extract descriptive of the process is from
the ‘Journal of Applied Chemistry’:——
“If a woven or spun fibre is to be examined it must first be disintegrated
into the single fibres, and any colour or finish must be removed as
completely as possible. Vertical and longitudinal microscopic sections are
next made. These are rendered transparent by glycerin or chloride of
calcium, and treated with tincture of iodine, made by simply dissolving
iodine in a solution of iodide of potassium. The excess of this tincture
is removed, a drop of dilute sulphuric acid added, and the sections
examined by the aid of the microscope.
_Linen Fibre._——Bundles of similar fibres, with a fine canal in the
centre, long, uniformly thick, and pointed at the ends. Longitudinal
section; the fibres are coloured blue, the canal yellow. Cross section:
regular polygons, loosely connected, coloured blue; centres yellow.
_Hemp._——Fibres aggravated; each fibre covered with a thin skin; coloured
yellow. They are thick and less uniform than the linen fibres. The ends
are thick and of the shape of spatulas, and become blue or greenish blue
with iodine. Cross section: irregular polygons, firmly connected; rim
yellow, the mass blue, the centre colourless.
_Cotton._——Longitudinal section: single fibres, spirally wound on their
own axis, with a central canal and broad ends; coloured blue by iodine.
The cross sections are rounded in the shape of kidneys, and coloured blue,
with yellow spots interspersed.
_China Grass._——Longitudinal section: fibres separated lengthwise, of
varying thickness. The interior canal is often filled with a yellow
granular substance, which is coloured brown by iodine. The fibre is turned
blue by iodine. Cross section: irregular, with re-entrant angles, and
little cohesion. The fibres are stouter than all other fibres, and are
turned blue by iodine.
_Jute._——Fibres strongly coherent, the ends undulating and difficult to
separate. Central canal wide, empty, and gently rounded at the ends;
coloured yellow. Cross section: polygons strongly coherent and regular,
much like those of hemp, but the central opening is larger; coloured
yellow, darker at the rim.
_New Zealand Flax._——Bundles of cells of the leaves, easily separated with
a needle into stiff little fibres, provided with a canal of uniform width.
The sides are rolled inwards, coloured yellow. The cross section resembles
that of jute, but the corners of the polygons are rounded off. They are
coloured yellow by iodine tincture.
=VEGETA′TION.= Vegetation (which is here employed in the sense of plants
in general) is very unequally distributed over the earth’s surface. Thus,
towards the poles plants are found, not only in diminished numbers
compared to their occurrence in warmer and more temperate regions, but
also of much smaller size or stunted growth. No plants at all are met in
the regions of eternal frost and snow, whilst in equatorial climes they
attain to the most gigantic proportions, and are possessed of the most
exquisite colours and perfumes, and yield the finest fruits. The habitat
of a plant will, of course, be that on which it finds the conditions
favorable to its existence and growth, in the shape of soil, climate,
moisture, geographical position, &c.
=VEGETATION (Metallic).= This name has been fancifully applied to the
following:——
LEAD TREE; ARBOR SATURNI. Take of sugar of lead, 1 oz.; distilled water,
1-1/2 pint; acetic acid, a few drops; dissolve, place the liquid in a
clear white glass bottle, and suspend a piece of zinc in it, by means of a
fine thread.
SILVER TREE; ARBOR DIANÆ. From nitrate of silver, 20 gr.; water, 1 fl.
oz.; dissolve in a phial, and add about 1/2 dr. of pure mercury.
TIN TREE; ARBOR JOVIS. From chloride of tin, 3 dr.; nitric acid, 10 to 15
drops; distilled or rain water, 1 pint; dissolve in a white glass bottle,
and hang in it, by a thread, a small rod of zinc.
_Obs._ In the above experiments the metals are precipitated in a very
beautiful arborescent form. It is curious to observe the laminæ shoot out,
as it were, from nothing, assuming forms resembling real vegetation. This
phenomenon results from voltaic action being set up between the liquid and
the metal.
=VEGETO-AL′KALI.= See ALKALOID.
=VEL′LUM.= A fine kind of parchment prepared from the skins of calves,
kids, and lambs. The skins are limed, shaved, washed, and stretched in
hoops or other frames, where they are scraped and trimmed with the
currier’s fleshing-knife, and next carefully rubbed down with pumice
stone; they are, lastly, polished with finely powdered chalk or
fresh-slaked lime, and then dried. A green colour is given with a solution
of crystallised verdigris, to which a little cream of tartar and nitric
acid has been added; and a blue colour, with a solution of indigo. The
surface is often finished off with white of egg, and subsequent friction.
The skins of sheep are commonly used for parchment; those of he-goats and
wolves for drum-heads; and those of the ass for battledores. The species
of vellum used for church services by binders is said to be prepared from
pig-skins. See POUNCE.
=VEL′VET COLOURS.= _Syn._ MAP STAINS, PAPER S.; LACCA FLUIDA, L. _Prep._
1. (BLUE.)——_a._ Dissolve litmus in water, and add 1/3 of spirit of
wine.——_b._ Dilute Saxon blue or sulphate of indigo with water. If
required for delicate work, neutralise the acid with chalk.——_c._ To an
aqueous infusion of litmus add a few drops of vinegar, until it turns of a
full blue.
2. (GREEN.)——_a._ Dissolve crystallised verdigris in water.——_b._ Dissolve
sap green in water, and add a little alum.——_c._ Add a little salt of
tartar to a blue or purple solution of litmus, until it turns green.——_d._
Dissolve equal parts of crystallised verdigris and cream of tartar in
water.
3. (PURPLE.)——_a._ Steep litmus in water, and strain the solution.——_b._
Add a little alum to a strained decoction of logwood.——_c._ Add a solution
of carmine (red) to a little blue solution of litmus or Saxon blue.
4. (RED.)——_a._ Macerate ground Brazil wood in vinegar, boil a few
minutes, strain, and add a little alum and gum.——_b._ Add vinegar to an
infusion of litmus until it turns red.——_c._ Boil or infuse powdered
cochineal in water containing a little ammonia or sal volatile.——_d._
Dissolve carmine in liquor of ammonia, or in weak carbonate of potash
water; the former is superb.
5. (YELLOW.)——_a._ Dissolve gamboge in water, and add a little alum.——_b._
Dissolve gamboge in equal parts of proof spirit and water. Golden
coloured.——_c._ Steep French berries in boiling water, strain, and add a
little alum.——_d._ Steep turmeric, round zedoary, gamboge, or annotta, in
a weak ley of subcarbonate of soda or potash.
_Obs._ The preceding, thickened with a little gum, are used as inks for
writing, as colours to tint maps, foils, paper, artificial flowers, &c.,
and to paint on velvet. Some of them are very beautiful. Those containing
litmus are, however, fugitive. It must be observed that those made with
strong spirit do not mix well with gum water, unless somewhat diluted with
water. Any other transparent colours or stains may be employed for
painting on velvet, as well as the above.