constituents of the urine which have crystallized out of that liquid at
some part of the urinary passage, and have remained as small particles
(gravel), or have concreted into large masses (stone, calculus). (See Pl.
XI, figs. 1, 2, 3.) In cattle it is no uncommon thing to find them
distending the practically microscopic tubes in the red substance of the
kidney, having been deposited from the urine in the solid form almost as
soon as that liquid has been separated from the blood. These stones appear
as white objects on the red ground formed by cutting sections of the
kidney, and are essentially products of the dry feed of winter, and are
most common in working oxen, which are called upon to exhale more water
from the lungs and skin than are the slop-fed and inactive cows. Little
water being introduced into the body with the feed and considerable being
expelled with the breath and perspiration in connection with the active
life, the urine becomes small in amount, but having to carry out all waste
material from the tissues and the tissue-forming feed it becomes so charged
with solids that it is ready to deposit them on the slightest disturbance.
If, therefore, a little of the water of such concentrated urine is
reabsorbed at any point of the urinary passages the remainder is no longer
able to hold the solids in solution, and they are at once precipitated in
the solid form as gravel or commencing stone. In cattle, on the other hand,
which are kept at pasture in summer, or which are fed liberally on roots,
potatoes, pumpkins, apples, or ensilage in winter, this concentrated
condition of the urine is not induced, and under such circumstances,
therefore, the formation of stone is practically unknown. Nothing more need
be said to show the controlling influence of dry feeding in producing
gravel and of a watery ration in preventing it. Calculus in cattle is
essentially a disease of winter and of such cattle as are denied succulent
feed and are confined to dry fodder as their exclusive ration. While there
are exceptions, they are so rare that they do not invalidate this general
rule. It is true that stone in the kidney or bladder is often found in the
summer or in animals feeding at the time on a more or less succulent
ration, yet such masses usually date back to a former period when the
animals were restricted to a dry ration.
In this connection is should be noted that a great drain of water from the
system by any other channel than the kidneys predisposes to the production
of gravel or stone. In case of profuse diarrhea, for example, or of
excessive secretion of milk, there is a corresponding diminution of the
water of the blood, and as the whole quantity of the blood is thus
decreased and as the urine secreted is largely influenced by the fullness
of the blood vessels and the pressure exerted upon their walls from within,
it follows that with this decrease of the mass of the blood and the
lessening of its pressure outward there will be a corresponding decrease of
urine. The waste of the tissues, however, goes on as before, and if the
waste matter is passed out through the kidneys it must be in a more
concentrated solution, and the more concentrated the urine the greater the
danger that the solids will be deposited as small crystals or calculi.
Again, the concentrated condition of the urine which predisposes to such
deposits is favored by the quantity of lime salts that may be present in
the water drunk by the animal. Water that contains 20 or 30 grains of
carbonate or sulphate of lime to the gallon must contribute a large
addition of solids to the blood and urine as compared with soft waters from
which lime is absent. In this connection it is a remarkable fact that stone
and gravel in the domesticated herbivora are notoriously prevalent on many
limestone soils, as on the limestone formations of central and western New
York, Pennsylvania, Ohio, and Michigan; on the calcareous formations of
Norfolk, Suffolk, Derbyshire, Shropshire, and Gloucestershire, in England;
in Landes in France, and around Munich in Bavaria. It does not follow that
the abundance of lime in the water and fodder is the main cause of the
calculi, as other poisons which are operative in the same districts in
causing goiter in both man and animal probably contribute to the trouble,
yet the excess of earthy salts in the drinking water can hardly fail to add
to the saturation of both blood and urine, and thereby to favor the
precipitation of the urinary solids from their state of solution.
The known results of feeding cattle a generous or forcing ration in which
phosphate of lime is present to excess adds additional force to the view
just advanced. In the writer's experience, the Second Duke of Oneida, a
magnificent product of his world-famed family, died as the result of a too
liberal allowance of wheat bran, fed with the view of still further
improving the bone and general form of the Duchess strain of Shorthorns.
Lithotomy was performed and a number of stones removed from the bladder and
urethra, but the patient succumbed to an inflammation of the bowels,
induced by the violent purgatives given before the writer arrived, under
the mistaken idea that the straining had been caused by intestinal
impaction. In this case not only the Second Duke of Oneida, but the other
males of the herd as well, had the tufts of hairs at the outlet of the
sheath encased in hard, cylindroid sheaths of urinary salts, precipitated
from the liquid as it ran over them. The tufts were in reality resolved
into a series of hard, rollerlike bodies, more or less constricted at
intervals, as if beaded.
When it is stated that the ash of the whole grain of wheat is but 3 per
cent, while the ash of wheat bran is 7.3 per cent, and that in the case of
the former 46.38 per cent of the ash is phosphoric acid, and in that of the
latter 50 per cent, it can easily be understood how a too liberal use of
wheat bran should prove dangerous if fed dry. The following table shows the
relative proportion of ash and phosphoric acid in wheat bran and in some
common farm seeds:
_Ash and phosphoric acid in bran and some common farm seeds._
--------------------+----------+-------------+---------------
Kind of grain. | Ash. | Phosphoric | Phosphoric
| |acid in ash. | acid in the
| | | entire feed.
--------------------+----------+-------------+---------------
|_Per cent_| _Per cent_ | _Per cent_
Wheat bran | 7.3 | 50 | 3.65
Wheat, grain | 3 | 46.38 | 1.3914
Oats, grain | 2.50 | 26.5 | .6625
Barley, grain | 3.10 | 39.6 | 1.2276
Bean, grain | 3.10 | 31.9 | .9864
Peas, grain | 2.75 | 34.8 | .957
Tare, grain | 3 | 36.2 | 1.086
Indian corn, grain. | 1.5 | -- | --
Rye, grain | 1.6 | 39.9 | .6384
--------------------+----------+-------------+---------------
Wheat bran, it will be observed, contains three times as much phosphoric
acid as is found in any of the other grains, and four times as much as
oats, beans, peas, or rye; so that if fed in excess it will readily
overcharge the urine with phosphates.
There is another point to be considered, however, in estimating this
danger. Wheat bran contains a far greater quantity of albuminoids and other
nitrogen-containing constituents than the common grains (these being made
up mainly of starch, which contains no nitrogen); and, all nitrogen-bearing
products contained in the blood and tissues being expelled from the body
mainly through the kidneys in the form of urea and (in cattle) hippuric
acid, it follows that the excess of urea formed when such feed is consumed
must load the urine with solids and bring it constantly nearer to the point
of saturation, when such solids (or the least soluble of them) must be
deposited.
The following table will show the relative amounts of the nitrogen-bearing
products in wheat bran and some of our common grains:
_Nitrogenous matter in wheat bran and some common farm grains._
-----------------+---------------+----------------+----------------------
Kind of grain. | Albuminoids | Woody fiber | Total nitrogenous-
| (nitrogenous).| (nitrogenous.) | bearing constituents.
-----------------+---------------+----------------+----------------------
| _Per cent_ | _Per cent_ | _Per cent_
Wheat bran. | 16.1 | 8 | 24.1
Wheat, grain | 12.5 | 1.8 | 14.3
Barley, grain | 12.4 | 2.7 | 15.1
Oats, grain | 11.8 | 9.5 | 21.3
Rye, grain | 10.6 | 1.7 | 12.3
Indian corn | 10.1 | 1.7 | 11.8
-----------------+---------------+----------------+----------------------
It will be observed that, with the exception of oats, none of the grains
contain more than two-thirds of the nitrogenous material present in the
wheat bran, while in the case of rye and maize there is practically but
one-half. Even in the case of oats the albuminoids, which are the more
digestible principles, and therefore those that are the most easily and
speedily converted into urea, are present only to the amount of two-thirds
of that which exists in the wheat bran. With such an excess of ash, of
phosphates, and of nitrogenous (urea-forming) constituents in wheat bran,
its tendency to favor the formation of calculi is fully explained. It must
not, however, be inferred that wheat bran is not a valuable feedstuff. The
inference is only that it should be fed with an abundance of water, as a
sloppy mash, or in combination with an abundance of roots, potatoes,
pumpkins, or other succulent aliment.
In this connection the presence of magnesia in the feed or water must be
named as favoring calculous formations in the urinary passages. The
explanation is that while the phosphate of magnesia thrown out in the urine
is soluble in water, the compound phosphate of ammonia and magnesia is
insoluble, and, accordingly, if at any time ammonia is introduced into
urine containing the phosphate of magnesia there is instantly formed the
ammonio-magnesium phosphate, which is as promptly deposited in the solid
form. The common source of ammonia in such cases is from decomposition of
the urea in fermenting urine. In order to produce this a ferment is
necessary, however, and therefore, as an additional prerequisite, the
presence of bacteria, or fungi, in the urine is essential. These ferments
may make their way from without along the urinary passage (urethra), and
their propagation in the bladder is greatly favored by the prolonged
retention of urine, as in case of spasm of the neck of the bladder or
obstruction by an already existing stone. Another mode of entrance of the
ferment is an unclean catheter used to draw the urine. Still another is the
elimination through the kidneys of the bacteria of infectious diseases, or
of such as, without producing a general infection, yet determine
fermentation in the urine. The precipitation is favored not only by the
production of ammonia, but also by the formation of viscid (colloid)
products of fermentation. In this sense bacteria are most important factors
in causing gritty deposits in the urine.
Another insoluble salt which enters largely into the composition of many
urinary calculi of the ox is carbonate of lime. This is derived mainly from
the lime in the feed and water and from the carbon dioxid formed by the
oxidation of the organic acids in the fodder. These organic acids, being
composed of carbon, hydrogen, and oxygen (without nitrogen), are resolved
by the addition of oxygen into carbon dioxid (CO_{2}) and water (H_{2}O).
The carbon dioxid unites with the lime in the blood to form carbonate of
lime, and in this state passes into the urine. Now, carbonate of lime is
soluble in water containing free or uncombined carbon dioxid, but is
precipitated whenever the latter is withdrawn. It is only necessary,
therefore, to have in the urine sufficient lime or other available base to
unite with all the free carbon dioxid in order to bring about the
precipitation of the dissolved carbonate of lime in the solid, crystallized
form; hence it is that, of all sediments in the urine of herbivora, this is
the most frequent and usually the most abundant.
A less common constituent of urinary calculi is the insoluble oxalate of
lime. In this case the lime is derived as before from the feed or water, or
both, while the oxalic acid is a product of the oxidation of organic acids
of the feed, less oxygen having been used than in the formation of carbon
dioxid. The final product of the complete oxidation of these acids is
carbon dioxid, but when less oxygen is furnished, owing to some disease of
the lungs or a disease of the nerve centers, which lessens the activity of
the breathing, then oxalic acid may be produced. If this oxalic acid comes
into contact with lime, it is instantly precipitated as crystals of oxalate
of lime.
Another inorganic substance at times found in urinary calculi is silica
(SiO_{2}). This contributes largely to giving stiffness to the stems of
growing plants, and in most of our cereals and grasses makes up a large
proportion of the ashes of the burned plant. It is found in the soluble
form in combination as silicate of potash, but at times is displaced by
oxalic or other acid and then appears as gritty, sandy particles in the
stem. This gritty, insoluble silica is especially noticeable among the
horsetails (_EquisetacÊceÊ_), bamboos, and sedges. The per cent of silica
in the ash of several common fodder plants is given below:
_Silica in ash of various fodder plants._
Ash of-- Silica.
_Per cent._
Wheat straw 67.6
Oats and husk 38.6
Oat straw 35.4
Barley straw 73.1
Rye straw 64.4
Rye-grass hay 64.57
Wheat chaff 81.2
Oat chaff 59.9
Barley awn 70.7
It is only soluble silica that is taken up into the system, and it is in
this form (usually as silicate of potash or soda) that it enters the urine,
but all that is wanted to precipitate it in crystalline form as a gritty
sand is the presence of oxalic or other acid having a stronger affinity for
its base (potash or soda).
Other conditions, however, enter largely into the causation of stone, or
gravel. A high density of urine resulting from a highly saturated condition
is often present for a length of time without any precipitation of solid
materials. Urea and carbonates may be present in excess, the feed may be
given dry, and drinking water may be deficient in quantity without any
deposition of stone or gravel. In such cases, the presence of
noncrystalline organic matter in the urine becomes an exciting cause.
Rainey and Ord have shown experimentally that colloid (noncrystallizable)
bodies like mucus, epithelial cells, albumin, pus, blood, hyaline casts of
the kidney tubes, etc., not only determine the precipitation of
crystallizable salts from a strong solution, but they determine the
precipitation in the form of globular masses, or minute spheres, which, by
further similar accessions, become stones, or calculi, of various sizes.
The salts that are deposited by mere chemical reaction without the
intervention of colloids appear in the form of sharply defined angular
crystals, and hence the rough, jagged crystals of oxalate of lime or
ammonia-magnesium phosphate. Heat intensifies the action of the colloids in
causing precipitation of the dissolved salts, so that the temperatures of
the kidneys and bladder constitute favorable conditions. Colloids that are
undergoing decomposition are also specially powerful, so that the presence
of bacteria or fungi causing fermentation is an important factor.
In looking, therefore, for the immediate causes of urinary calculi we must
accord a high place to all those conditions which determine the presence of
excess of mucus, albumin, pus, blood, kidney casts, blood-coloring matter,
etc., in the urine. A catarrhal inflammation of the pelvis of the kidney,
of the ureter, or of the bladder, generating excess of mucus or pus;
inflammation of the kidneys, causing the discharge of blood, albumin, or
hyaline casts into the urinary passages; inflammation of the liver, lungs,
or other distant organ, resulting in the escape of albumin in the urine;
disorders of the liver or of the blood-forming functions, resulting in
hematuria or hemoglobinuria; sprains or other injuries to the back, or
disease of the spinal marrow, which cause the escape of blood with the
urine; the presence in the bladder of a bacterial ferment, which determines
the decomposition of the mucus and urea, the evolution of ammonia and the
consequent destruction of the protecting cellular (epithelia) lining of the
bladder, or the irritation caused by the presence of an already formed
calculus, may produce the colloid or uncrystallizable body that proves so
effective in the precipitation of stone or gravel. It has long been known
that calculi almost invariably form around any foreign body introduced into
the kidney or bladder, and I have seen a large, calculous mass surrounding
a splinter of an arrow that had penetrated and broken off in the body of a
deer. The explanation is now satisfactory--the foreign body carries in with
it bacteria, which act as ferments upon the urine and mucus in addition to
the mechanical injury caused by its presence. If such a body has been
introduced through the solid tissues, there is, in addition, the presence
of the blood and lymph derived from the wounded structures.
CLASSIFICATION OF URINARY CALCULI.
Urinary calculi are most conveniently divided according to the locality in
which they are found. Thus we find first renal calculi, formed in the
kidney (Pl. XI, fig. 1), and which for cattle must be again divided into
calculi of the uriniferous tubes and calculi of the pelvis. The second
class are named ureteral calculi because they are found in the duct leading
from the kidney to the bladder (ureter). The third class are the vesical
calculi, from the bladder or vesicle in which they are found. The fourth
class are the urethral calculi, and are found in the duct leading outward
from the bladder through the penis (urethra). The fifth and last class are
the preputial calculi, since they are found within the sheath of the penis
(prepuce).
Calculi may also be classed according to their chemical composition and
this has the advantage of suggesting the special cause of each as found in
the feed, water, soil, or general conditions of health. This classification
affords no guide to their location or symptoms, as calculi of the same
chemical composition may be formed at any part of the urinary passages, as
those formed in the kidney may pass on through all the various passages
outward, unless it is found at any point of their progress that they have
grown so large that the passage will not admit them. The following are
among the concretions found in the various parts:
(1) _Coralline calculi._--These are of a dull-white color and irregular
surface, like coral. They are made up of hard and resistant layers evenly
deposited around a central nucleus. (Pl. XI, fig. 3.) Their specific
gravity is 1,760, water being 1,000, and they contain 74 per cent of
carbonate of lime with some carbonate of magnesia, organic matter, and a
trace of carbonate of iron. Yellowish-white, smooth, round calculi of the
same chemical composition are met with.
(2) _Pearly calculi._--These are more frequent than the first-named
variety. They are very hard and smooth on the surface, reflecting a play of
various colors after the fashion of a pearl. This peculiarity appears to be
caused by the thinness and semitransparency of the supposed layers. They
have a specific gravity of 2,109 to 2,351, and nearly the same chemical
composition as the coralline variety. Golding Bird found a specimen of this
kind formed of carbonate of lime and organic matter only.
(3) _Green calculi_ (_metalloid calculi_).--These are usually small and
numerous, as they are exceedingly common. They are of a very hard
consistency, and have a clear-polished, greenish surface of almost metallic
brilliancy. They have a specific gravity of 2.301 and a composition almost
identical with the second variety.
(4) _White calculi._--Pure white, smooth, lustrous calculi are rare. They
have a specific gravity of 2.307, and contain as much as 92 per cent of
carbonate of lime with carbonate of magnesia and organic matter.
(5) _Ammonio-magnesium calculi._--These are of a grayish color and a very
rough, crystalline surface, which proves very irritating to the mucous
membrane. They have a specific gravity of 1.109 to 1.637, and are composed
chiefly of ammonio-magnesium phosphate, oxalate of lime, and organic
matter, with a little carbonate of lime and magnesia.
(6) _Siliceous calculi._--These are clear, smooth, and hard, and usually
spherical. They have a specific gravity of 1.265 to 1.376, and contain 57
per cent of silica with carbonates of iron and magnesia, organic matter,
and traces of iron. In other specimens of siliceous calculi there was a
specific gravity of 3.122, and there was 79 to 85 per cent of carbonate of
lime together with carbonate of magnesia, and iron, silica, and organic
matter. Others are almost exclusively made of silica.
(7) _Oxalate of lime calculi_ (_mulberry calculi_) (Pl. XI, fig. 2).--
These are characterized by their extremely rough, angular surface, formed
by the octahedral crystals of oxalate of lime. Their specific gravity may
be 3.441, and they contain oxalate of lime to the extent of 81 per cent,
together with carbonates of lime and magnesia and organic matter.
(8) _Gravel_ (_pultaceous deposits_).--Simple crystals may be met with at
any point from the kidneys to the external opening at the end of the
prepuce (sheath), and they may appear singly, as crystals, or they may
accumulate in masses of fine spherical crystals almost like dirty powdered
chalk suspended in water. In the ox this is especially common as a
collection in the sheath, distending that into a soft, doughy swelling.
FORMS OF CALCULI IN DIFFERENT SITUATIONS.
Apart from the rough crystalline surfaces of the calculi of oxalate of lime
and ammonio-magnesium phosphate, the general tendency is to a smooth, round
outline. At times, however, they show more or less flattening with rounded
angular edges, caused by the contact and mutual friction of two calculi.
Sometimes two or more stones lying together become united into one by a new
external deposit, and the resulting mass then shows rounded swellings on
opposite sides. The large calculi occupying the pelvis of the kidneys
usually show a central part having the outline of the main cavity of the
pelvis and two or more projections that have been molded into the
corresponding branches or channels which lead to corresponding lobes of the
kidney. In winter and spring small concretions in the form of plates are
often met with in the branches of the pelvis, having been formed and molded
in the confined space between the projecting papilla and the surrounding
cuplike branch of the pelvis. Finally, the pulplike deposits in the sheath
and elsewhere are made up of globular masses, individually so small as to
be often practically microscopic.
STONE IN THE KIDNEY (RENAL CALCULI).
[Pl. XI, fig. 1.]