HIDES AND SKINS
The hides and skins of animals form the principal raw material of
the tanner. Technically, the term "hides" is applied to the skins of
the larger animals, while the word "skins" is used in the case of
the smaller animals. Thus, the tanner speaks of ox, cow, bull and
horse _hides_, and of calf, sheep, and goat _skins_. There is an
intermediate size between a full-grown calf skin and a small hide,
and this is known as a "kip," but the line of demarcation is not very
clear.
Buyers often settle the difficulty by examining the growth marks
and the irregular substance of the skin, and, if these are marked
features, it is classified as a kip. The condition of the hides of
cattle is usually inferior during the six months after the animal
has become a yearling. East India tanned hides, which are largely
imported into England, are frequently described as E.I. "kips" in
the trade. This is hardly accurate, but the mistake is probably
due to the small size of full-grown Indian hides, which are very
little larger than the average European kips. It is interesting
to observe that furriers always refer to both their raw material
and the finished product as skins, irrespective of the size of the
fur-bearing animals. Most of the skins of wild animals are dressed
without removing the hair or fur, and this is quite a distinct trade
from leather manufacture, the only exception being the dressing
of closely cut and fine-haired calf skins for slippers and fancy
articles.
Practically every country in the world contributes to the supply of
hides and skins, but there are a few countries which are far in
advance of the others in the industries of cattle and sheep-raising.
The sources of tanners' raw material have undergone great changes
since the establishment of freezing and chilling stores for the
preparation of meat for export, and the market prices of hides are to
a large extent controlled by the supply in North and South America,
South Africa, and Australia. Whether or not the concentration of
these huge meat works into two or three centres is likely to benefit
the leather trade is a debatable point. The flaying, trimming, and
curing of hides in these establishments are certainly superior to
the work done by the average butcher, while, owing to the large
numbers of cattle slaughtered, the hides can be closely selected. On
the other hand, the value of hides and skins has risen enormously
in the last decade, the period coincident with the rapid growth
of the chilled and frozen meat industry, but the increased use
of leather in many directions may be mainly responsible for the
higher cost of the raw material, although it is obvious that the
concentration of the chief supplies of hides in a few lands must
tend to increase the severity of the competition among buyers. Apart
from the high prices of the hides, the concentration of the meat
industry in large chilling and freezing works has had the effect
of increasing the prices of beef and mutton, which are now higher
in price than freshly-killed English meat was a few years ago.
It appears to have been a grave error on the part of the British
Government when they stopped the imports of live cattle owing to the
fear of foot-and-mouth disease being communicated to domestic herds.
The disease has broken out in several places since the embargo was
imposed, so that the theory that the infection was only carried by
imported live cattle has been clearly disproved. The butchering of
cattle provides a large amount of work in subsidiary industries,
and the Government embargo on the importation of live cattle has
caused a great deal of distress in Deptford and Birkenhead, where
large abattoirs were erected for the reception of live cattle, which
used to be imported in fairly large numbers. There is no danger
of foot-and-mouth disease getting beyond the abattoirs or of the
slaughter of diseased cattle for food, and both tanners and butchers
hope to see the removal of the embargo. So far as possible, each
country should raise its own cattle to provide its own meat supply,
and this principle is recognised by many countries which prohibit the
import of foreign meat: but, owing to the rapid growth of populations
in industrial countries, with the consequent increase in the value of
land, it has become impracticable to raise enough cattle to supply
domestic needs. Even the United States of America, which formerly had
a great cattle-raising industry, has lately been obliged to import
live cattle to meet the requirements of its inhabitants. Similar
conditions prevail almost throughout Europe, and tanners have to look
to South America, Australia, and Africa for large supplies of raw
hides, although there are still some tanners in the United Kingdom
who use only the hides produced in this country.
The bulk of the production of hides and skins in the United Kingdom
is disposed of at weekly public auctions in the principal towns:
London, Manchester, Liverpool, Leeds, Birmingham, Newcastle, and
Glasgow being the largest centres of distribution. However, there
is still a large quantity bought by private treaty, and opinions
are divided as to which is the better method of buying. Before the
establishment of public auctions, hides were very cheap, but tanners
were unable to get a good selection, although, for sole leather, that
was not a very important matter. Public auctions have become so
firmly established that it would be impossible for tanners to revert
to the old system even if they desired it. The competition of private
buyers with the auction markets has certainly benefited the butcher
at the expense of the tanner, and the weighing and classification
of hides ultimately became so irregular in many markets that the
Tanners' Federation of the United Kingdom had to take strong
action not long ago to protect their interests. They demanded the
appointment of an independent inspector at each market to check the
weighing and sorting of the hides, but this was successfully resisted
by the market proprietors, who eventually agreed to the tanners
appointing travelling inspectors to visit the markets periodically.
The system is said to have improved matters.
The English markets do not collect enough hides to permit their close
sorting, so that, while the hides are graded according to weight and
quality and the sex of the animal, the question of varying substances
is generally ignored. There is usually a difference of 10 lb. in each
class where the hides are sorted by weight Ox, cow, heifer, and bull
hides are sold separately, as each sort has a different value. Bull
hides are comparatively poor in quality, owing to their irregular
substance and strong growth marks in the neck. Ox hides are the most
suitable for sole leather and belting, while cows' and heifers' are
used mainly for dressing hides, which are finished into bag, case,
strap, and boot leathers. The hides known as Scotch and Hereford
runts are the best of those produced in the United Kingdom, as they
are well-grown, compact, and well-suited to the making of sole
leather and belting. The grading of the weight of these hides at the
auction markets is generally as follows: 100 lb. and above, 90-99
lb., 80-89 lb., 70-79 lb., 60-69 lb., 59 lb. and less. This does not
give an ideal classification, as hides vary so much in texture and
substance, and it is quite possible to find spready hides of poor
substance and quality which would be heavier than a small but compact
and well-grown hide. It would be better from the tanner's point of
view if the hides were selected according to substance and quality.
There are not many bull hides grown in the United Kingdom, and in
many markets they are not classed by weight but simply into best and
secondary qualities. Horse hides are of even less value than those
of bulls, owing to their weaker texture and irregular substance.
That part of the skin under the mane is almost worthless, while the
flanks and sides are only useful for a secondary class of boot upper
leather, although some fairly good patent sides have lately been
produced from horse hide, which is suitable for that purpose owing
to its soft grain and pliable texture when tanned. The most valuable
part of a horse hide is the butt, which consists of the part known
as the "shell." This shell is covered with an extremely fine grain
which is not found in any other part of the hide. The well-known crup
leather is made from the shell of the horse hide.
In addition to hides, there are fairly large quantities of calf
and sheep skins sold at the weekly auctions, but veal is not such
an important article of food in England as it is on the Continent.
Sheep skins are far more numerous, as Great Britain is a big
mutton-consuming country. Home supplies of both hides and skins have
been greatly reduced, however, by the immense import of frozen and
chilled meat.
Although the domestic supply of hides and skins is quite inadequate
to meet the needs of British tanners, a large proportion is exported.
American tanners buy large quantities of the best hides and pickled
sheep skins. The latter are dewoolled and preserved by a process of
pickling with formic or sulphuric acid and salt before exportation.
Those preliminary operations are the work of the fellmonger. Nearly
all of the horse hides produced in the United Kingdom are, or were
before the War, sent to Germany, and British leather-dressers appear
to have lost the art of finishing horse hide, or are unable to
convert it into leather profitably.
The interchange of raw hides between various countries, and even
between those where leather manufacture is an important industry, is
somewhat remarkable, and only goes to prove that the concentration
of a particular industry in one or two centres of the world gives
these places a great advantage in regard to labour, organisation,
and technical skill, even over those countries where the raw
material is plentiful. Theoretically and economically it should
be advantageous to establish tanneries close to the supply of raw
hides, since the latter, under present conditions of preservation,
steadily deteriorate from the time they are removed from the carcase
until they reach the tannery. In some countries the methods of
preserving hides are actually so bad that the hides have often lost
half of their value before the tanner gets them. Two or three of the
largest American meat-packing establishments have erected or taken
over tanneries to deal with raw hides, one of their by-products.
Tanneries have also been erected near some of the large meat works in
the Argentine, but the development of the leather trade there is by
no means rapid, and at present the United States of America is the
largest leather-producing country in the world. Germany, France, and
the United Kingdom come next in the order named.
South Africa is an important source of supply of raw material, and
large quantities of Cape hides are sent to England. The production of
raw hides there is likely to be on a very large scale in a few years'
time, as the raising of Afrikander and other breeds of cattle is sure
to become an important industry now that the ravages of the terrible
disease, known as "tick," have been checked. China is another large
hide-exporting country; most of the hides from this source are
dried in the open air and are generally arsenicated to prevent the
ravages of insects. Immense quantities are also provided in all
other populous countries, but the demand for leather is generally
greater than the production of raw material in those countries. India
is a noteworthy exception to this general rule; the production of
Indian hides is enormous, and, although the leather trade is being
developed, there is a large surplus of raw hides and skins for
export. Large quantities are roughly tanned, however, and exported to
England, Germany, France, and other European countries to be dressed
and finished. The greater proportion of these hides and skins is used
for the making of shoe leather, while a good quantity is used for bag
(hide) and imitation morocco (goat) leathers.
Naturally, there is in the aggregate a considerable supply of raw
hides and skins from other parts of the world in addition to that
from the countries specially named, and new sources are being
frequently found.
It would be impossible to describe the characteristics of the
numerous varieties of hides and skins except in a full-sized
text-book, but a brief description of the principal sorts may be
given.
Some of the varieties produced in the United Kingdom have already
been described. In the main, there is not a great deal of difference
in the hides of various breeds, but there is a type of well-grown and
stout hides specially suitable for sole and belting leather; this
class is known as runts, and these hides are obtained from the Scotch
and Hereford breeds of cattle. The Scotch runts from the Highland
cattle are more valuable than any other class of hide found in the
United Kingdom; unfortunately, the production is small. Irish cattle
also yield good hides, but in England the interests of the cattle
owner, or feeder, are in conflict with those of the tanner, for the
system of artificially fattening cattle with oil cakes tends to make
the hides very greasy and weaker in the fibres than those hides from
animals which are reared on natural food-stuffs.
This grease is very difficult to remove and reduces the selling value
of sole leather by about 2d. per lb. The use of a borax solution for
soaking partially removes the grease, while it has been proposed that
the pelts should be treated with a solution of hyposulphite of soda
just before placing them in the tan liquors. A drawback of the latter
process is that a little weight is lost in the finished leather.
The trouble caused by the presence of a large quantity of natural
grease is even more pronounced in sheep skins than in cattle hides.
Naturally, a sheep arrives at maturity in about two years; but by the
modern system of intensive feeding with oily food-stuffs it can be
fattened in about ten months. This is obviously a great advantage to
the sheep-breeder; in other respects it is an unsatisfactory method,
for the mutton is not so well matured, and, therefore, is not so
nourishing; it contains too large a proportion of fat, and the skins
are very greasy and weak in fibre. The excess of grease does not
detract from the value of the wool, and may even be beneficial.
There are several varieties of sheep in the United Kingdom, with
widely different characteristics. A fellmonger should have a
good knowledge of the skins of various breeds in order to buy the
particular sorts that will meet the requirements of his customers,
as his business is to separate the wool from the skins and to
supply the former to the woollen factories and the latter to the
leather-dressers. He has, therefore, to study carefully both the wool
and pelt markets. While some breeds of sheep yield fine long wool of
bright lustre, others have comparatively short-stapled, and "kempy"
wool. Between these two classes, there are numerous grades, and the
task of sorting the various qualities of wool in those fellmongeries
where several classes of skins are worked is by no means easy. It is
a generally accepted axiom that the pelt (_i.e._, the skin denuded
of wool) is weaker in fibre in those skins which yield the finest
and best wool. In support of this, the Welsh mountain sheep may be
cited. This sheep has short, curly wool, but its skin is tough and
strong on the grain. In fact, it is about the only breed suitable for
roller leather, which is used in the cotton industry for covering the
drawing rollers of spinning-machines. Most of this leather is made in
North Wales, whence it is exported to every country where the cotton
industry is carried on.
Notable exceptions of the general rule regarding the relative
qualities of wool and pelts are found in two or three English
varieties, namely: the Lincolns, Leicesters and black-faced Suffolks,
which produce both fine wool and large pelts of good quality.
Other useful British breeds are the Southdowns, Devons, Shropshires,
Wensleydales, Scotch black-faced, Cotswolds, and Kerrys. Of the
imported varieties, the New Zealand and Cape sheep skins are the
best. The former, principally merino stock, not only provide very
fine wool, but also pelts of choice quality and large pattern.
Although the quality of the wool of Australian merino sheep is
little, if any, inferior to that of the New Zealand type, the skins
are not so good in quality, due, no doubt, to the hotter climate,
which is favourable to the breeding of insects and other pests which
damage the skins. The Cape sheep provide a skin which is quite
different in texture from that of any other breed. It has a certain
looseness of texture and softness of grain which make it particularly
suitable for the manufacture of glove leather.
South America is another large sheep-breeding country; but the skins
of this variety are not largely imported into England, most of them
being sent to Mazamet, the great centre of the fellmongering industry
in France. Buenos Aires skins are the most favoured of the South
American skins, owing to their large size and good substance. Monte
Videos are also very fine skins.
Smyrnas and Bagdads are other well-known varieties, but they are
generally imported in a rough-tanned condition, or, as it is known
technically, "in the crust." Leather-dressers finish them for
various purposes, but mainly for boot and shoe lining leather. When
properly tanned by the natives, these skins produce a supple finish,
especially those of the Smyrna variety. Unfortunately, many lots are
merely coloured on the surface with the tan liquor, with the result
that they dry hard and tinny; such partially-tanned leather is very
difficult to finish and is rarely satisfactory. Even when the tannage
is completed elsewhere before finishing them, they never produce such
good leather as skins properly tanned in the first instance.
Russia is another important country for the production of all kinds
of raw hides and skins suitable for leather manufacture. American
tanners buy very largely from this market, and a few enterprising
firms even send their own representatives to the great annual fair
held at Nishni Novgorod, where large quantities of dried hides and
skins, besides many other kinds of produce, are offered for sale.
British tanners take comparatively little interest in this important
supply, but, as a result of the great European War, an increase of
trade between Russia and the United Kingdom is anticipated, although
the Russian leather trade is developing rapidly and will absorb
increasing quantities of native raw material.
Excepting a few in Ireland, raw goat skins are not produced in Great
Britain. The chief drawback to goat breeding there is a somewhat
inexplicable aversion on the part of the public to the flesh of
goats; although another reason may be the destructive nature of the
animals themselves, for they devour and uproot anything edible that
comes in their way. It is, perhaps, unfortunate that some of the
large areas of uncultivated land in Great Britain are not given up
to the breeding of goats on a large scale, since these hardy animals
will thrive on rough, hilly lands. Apart from the value of the meat,
it might be a paying proposition to rear large herds of goats for
the supply of milk (which is more nourishing than cows') and skins.
Leather-dressers are, therefore, dependent on imported supplies,
of which the principal sources are India (North-Western District),
Mexico, Arabia, Africa, South America, and several European countries.
Goat skins from the main sources of supply vary very much in
quality--even those produced in the same country. In India, for
example, skins may be obtained in some districts which can be made
into leather to sell at about 5d. per square foot; from another
district, when finished into the same kind of leather, say glazed
kid, they may be worth 1s. 4d.[1] per foot. Fineness and clearness
of grain and good substance are the main essentials of a first-class
goat-skin leather; unfortunately these qualities are rarely combined
in one class of skin, and there is a decided surplus of light thin
skins which are hardly saleable, even for ladies' shoes. Some
American shoemakers overcome this difficulty by pasting a piece of
cloth on the back of the skin. In fairness to the buyer, the boots
made of such leather should be specially marked, as the wearing
quality of a backed thin leather is not to be compared with one
naturally stout.
[1] It must be understood that, owing to the war, these prices
have been greatly increased.
The skins of goats are used for many purposes besides the
manufacture of the famous glacé kid leather; gloves, moroccos for
bookbinding, upholstery for furniture, fancy articles such as purses,
pocket-books, bags, and ladies' belts all require large quantities of
goat and kid skins. It may be pointed out here, however, that quite
nine-tenths of the so-called kid gloves are made of lamb and sheep
skins. In appearance, there is very little difference between the
real kid and the lamb skin gloves, but the former are more durable
and warmer in wear than the latter.
With an enormous range of qualities, it is a difficult task for the
goat-skin dresser to find the most suitable sorts for his trade.
The skins used in the glove industry are largely obtained from
the Near Eastern countries, Arabia, Austria, Spain, and the Cape.
The selections best suited to the making of glazed and "patent"
(japanned) kid are found in the North-Western provinces of India,
Brazil, China, Russia (especially the Asiatic provinces), Mexico,
the Cape, and Arabia. The Indian goats known as the Patnas, which
are collected in the district of Behar, are commonly supposed to
be the best in the world, chiefly because of their fine grain and
stout substance; but the best Brazilian and Mexican skins are
equally good in quality. The best moroccos for fancy articles are
made from Continental skins, and in this respect Germany has the
great advantage of a good supply of native skins. Norway and Spain
also provide skins suitable for real morocco leather. A very large
quantity of Indian-tanned goat skins are imported into European
countries and dressed for "morocco" leather. There should be a
distinctive name for this class of leather, as, although it is
similar in appearance, it is not nearly so good in quality as the
real morocco.
In addition to cattle hides, sheep, and goat skins, which are the
main supply of raw material for leather, other kinds of hides and
skins are utilised. Horse hides, which, in the United Kingdom, are
graded according to size and quality in four or five selections and
sold by the piece, are largely used on the Continent, and especially
in Germany; nearly all of the British production being sold to that
country. When chrome tanned, these hides produce quite a serviceable
upper leather of good wearing quality, but, owing to their somewhat
loose texture, the characteristic grain of box calf cannot be
reproduced naturally, and the surface of the leather has, therefore,
to be printed. This style of finished leather does not meet with the
favour of British boot manufacturers, and the industry has not been
greatly developed in consequence. In view of the increasing cost of
other kinds of leather, however, more attention may be paid to that
made from horse hide, but the supply of this raw material is very
small compared to the production on the Continent, where horse flesh
is consumed freely. Russia produces large quantities of horse hides
and colt skins, most of which are exported to the United States of
America, where they are made chiefly into japanned, or so-called
"patent," leather, which commands a very high price in relation to
the cost of the raw material.
Next in importance to horse hides is the pig skin, which produces a
wonderfully tough leather. The pig skin leather industry is chiefly
confined to Scotland and Germany, the reason being that the skins are
left on the carcases in the other parts of the world. On the average,
a pig skin is worth about 6s., yet it is seldom removed from the
carcase. One reason is the great difficulty of flaying the animal; it
appears to be almost impossible by present methods to remove the skin
without cutting away a large quantity of fat, and the value of the
skin compared to the loss of weight of the meat offers very little
inducement to remove the skin, in addition to which, the custom of
leaving the rind on bacon and pork effectually prevents any attempt
at present to increase the supply of pig skins. This is a great loss
to the leather trade, for the pig skin is particularly suitable for
saddles and various kinds of strong leather goods. Imitation pig-skin
leather is made from hides, shoulders, bellies, or persians, but real
pig skin is distinguished from the imitation by its peculiarly marked
grain, formed of groups of three small holes which penetrate well
into the skin and form part of the sheaths of the pig's bristles.
Among other skins useful for leather are those of the wallaby,
kangaroo, dog, lizard, crocodile, alligator, ichneumon, frog
(Japanese), deer, antelope, and chamois, while it is said that even
rabbit skins have been pressed into service in Germany, though they
cannot have much value owing to their small size and thin substance.
Dog-skin leather wears well, mainly on account of the large amount of
natural grease present in the skin, but the supplies are naturally
small. The hides of the walrus, elephant, rhinoceros, hippopotamus,
and other wild animals are also tanned in small quantities, walrus
leather being well adapted for knife and sword polishing.
The mammals also contribute their quota to the supply of raw material
of the leather trade, the seal perhaps, being the most important.
This refers to the hairy seal hunted off the North American coast.
The raw skins are shipped chiefly from Newfoundland, where the
industry of seal fishing is well organised and provides employment
for about 6,000 men. The seal caught in the North Atlantic Ocean is
hairy and quite distinct from the fur seal captured in the Arctic
Ocean off Alaska. The skin of the hair seal is only suitable for
making into leather, but there is a layer of fat underneath it which
furnishes a valuable raw material for the manufacture of oils and
soap. The skins are salted and shipped to America and England. They
are easily distinguished from other kinds of commercial hides and
skins by the oily appearance of the flesh side.
According to an American Consular Report, the results of the fishing
during the season 1913 were satisfactory. The total number of seals
captured was 272,965, which were valued at £98,800. The number of
skins exported was 212,285, valued at £64,300, of which the United
States of America bought 151,355, the United Kingdom 60,754, and
Canada 176.
The porpoise, or sea hog, has a very useful hide which, when dressed,
makes a tough leather suitable for laces. The hides of other
cetaceous mammals, such as the whale and narwhal, are convertible
into useful leather. The British "porpoise" laces are generally made
from the skin of the white whale (_beluga_).
DEFECTS OF RAW HIDES AND SKINS
A remarkable feature of the leather trade is the great waste due
to the careless preparation of a large number of hides and skins.
Naturally, owing to their greatly increased value in recent years,
there has been a decided improvement, but much loss occurs every day
from damage to hides which ought to be avoided. The chief faults are
in flaying and curing, but there are other important defects due to
natural causes.
Bad flaying may be due (1) to cutting holes in the hides or skins;
(2) to "scoring" or "siding" (_i.e._, cutting into the hide without
going completely through), this generally occurring in the flanks or
sides which are the most difficult parts of the hide to remove from
the carcase; and (3) to mis-shaping the hide, which ought to be left
square.
Any or all of these defects may be found in a single hide. Despite
the active work of several proprietors of hide markets and the
tanners' federations the proportion of badly-flayed hides in England
constitutes a serious loss, which, however, may not fall directly on
either the butcher or the tanner, for the former may save in wages
by employing an inexperienced slaughterman, while the tanner pays a
reduced price for the hide.
The losses due to bad flaying and curing in the United Kingdom
are mainly attributable to the butchers' preference to kill these
beasts in their own back-yard rather than in a public abattoir.
Many of these small private slaughterhouses ought to be condemned
by the authorities; but very few people outside those immediately
interested have taken the trouble to inspect a modern public abattoir
where everything is provided to carry on the work expeditiously and
hygienically. On the Continent, where the conservatism of traders is
not permitted to interfere with the public welfare to such an extent
as it is in England, public abattoirs have become quite a feature in
many cities, and one of the principal results of the system has been
a remarkable improvement in the preparation of raw hides and skins
for the tanner. In fact, a mechanical method of flaying has been
invented in Paris, and is used extensively at the public abattoirs,
by which hides are removed from cattle without a single mark or
scratch. The method is known as _dépouille mécanique_ (mechanical
flaying) and consists in forcibly removing, by means of a windlass
worked by electric power, the portions of hide which adhere firmly to
the carcase and which are found over the ribs, the buttocks, and the
tail. The remaining part of the hide can be easily removed with the
ordinary butchers' flaying knife or with a heavy hammer of special
design. The apparatus required to carry out the mechanical method of
flaying, beyond the fixtures in the abattoirs where the process is
adopted, consist of two lengths of chain to hold the carcase firmly,
two special hammers, and one pair of strong pincers; the cost of one
set is about £4. Mr. Gaston Tainturier, of Paris, is the inventor of
this system, which has added thousands of pounds to the incomes of
Parisian butchers.
Figure 1 is from a photograph taken at the Islington (London)
Abattoir, where a demonstration of the process was given by Mr.
Tainturier in February, 1913.
Naturally, this method cannot be adopted in small slaughterhouses
in back-yards, but is readily adaptable to public abattoirs, where
practically all of the heavy work is done by electrical power. This
exemplifies only one of several advantages of modern abattoirs over
private slaughterhouses.
Although it cannot be expected that the English butchers will readily
change their prejudice against modern abattoirs, they are slowly but
gradually improving the flaying process in view of the high prices
paid for perfect hides. The most progressive of the proprietors of
the English hide markets are offering money prizes to slaughtermen
for the best flayed hides. Strictly speaking, this encouragement
should come from the butcher, who receives the benefit of increased
prices for hides removed without a scratch. The Tainturier system,
however, gives better results, no matter how well the hides are
removed with the knife. The method is not patented, and it is open to
anyone to adopt it merely for the cost of the apparatus, yet, despite
this gain, no butcher outside France and Belgium has yet adopted the
method, although the trade is losing hundreds of pounds every week
through bad flaying.
Several other systems of improved flaying have been devised, and
some of them patented, but very few have been adopted on a practical
scale. One of the most useful consists of fixing a safeguard about
a quarter of an inch from the edge of the knife; this prevents the
possibility of cutting holes into the hide, although it does not,
of course, prevent scoring, which is a serious defect in hides made
into sole leather. A safe method is to use a sharp knife of hard
wood, such as hickory, which has been successfully tried in one of
the large American meat-packing establishments. The hides from these
abattoirs are generally well-flayed, properly cured, and closely
trimmed, with the result that they command higher prices than any
other class of salted hides. The quotations for "packer" hides are
followed with keen interest by tanners in all parts of the world.
[Illustration: FIG. 1
MECHANICAL FLAYING
(_dépouille mécanique_)]
Another useful method of preventing damage to the hides by cuts with
a knife is that invented by Mr. E. Pim, a Liverpool hide factor.
The apparatus used is known as the tail extractor. It is of simple
construction, consisting of four pieces of iron riveted together
loosely in the shape of a diamond with a clamp attached to
secure the tail. The hide is then forcibly removed from the tail
and the buttocks by pulling it downward (Fig. 2). The importance of
this operation can be gauged from the fact that by the use of the
butcher's knife both of these parts of the hide are often cut very
badly.
[Illustration: FIG. 2
PIM'S SYSTEM OF FLAYING]
Even the apparently trivial matter of removing the hide from the
cheeks and face is economically important, for, unless those parts
are removed so as to get the maximum surface, they are only fit to
be cut off and thrown in a pit with other pieces and roundings which
are made into glue.
Imperfect preservation is another serious form of damage to hides and
one that cannot be easily remedied in some of the hot climates. Hides
and skins may be simply dried, salted and dried, wet-salted, treated
with arsenic solution and dried, brined or pickled with acid and
salt; of these methods the last-named is the most effective, but is
not practicable, or, at least, has not yet been applied practically
to the cure of hides and calf skins. Salt is not available, or is too
costly in most tropical countries; hence, Chinese, Indian, Mexican,
Colombian, and Arabian hides and skins are generally exported in
a dry condition. Even when the hides are dried under the best
conditions in a cool and shady place, they are of less value than a
fresh or a wet-salted hide, owing to a certain loss of gelatinous
matter in softening them before they can be placed in the lime
liquors. But it not infrequently happens that hides are dried by
exposure to the hot sun, or perhaps in a strong current of air. In
either case, the hide is much reduced in value and may be irreparably
ruined. The effect of submitting hides to these conditions is that
the exterior surface becomes rapidly dry and, naturally, contracted,
so that the air or heat cannot reach the interior, which retains
moisture. This moist inner layer may be quite thin, but it contains
sufficient nutrient to develop putrefactive organisms, so that when
the hide is soaked in water it practically falls to pieces. The
effect of hot sun or heat of any kind is, of course, disastrous to
raw hides and skins, and there have been not a few claims on shipping
companies as the result of storing hides near the boilers of ships.
Salt is almost invariably used for curing both hides and calf
skins, but though it is a good preservative it has one or two minor
defects. It contains too much water, and is liable to contain traces
of iron which is inimical to both raw hides and leather in process
of manufacture. Common salt is also liable to cause stains which
cannot be removed in later processes, and which are even accentuated
in the tan liquors. One trade chemist attributes these stains to
the presence of calcium sulphate (Ca. SO_{4}) or gypsum in the
salt, which is converted into calcium phosphate by the action of
the phosphoric acid in the nuclei of the hide on the sulphate of
calcium. Another well-known technical chemist is certain that stains
are produced by the growth of bacteria, and to prove his assertion
prepared in gelatine several cultures from salt-stained skins.
Practical men generally attribute the stains to the presence of
blood on the hides or skins at the time of curing, and the majority
of the stains are probably due to this cause, although the presence
of calcium sulphate as an impurity of the salt would undoubtedly
contribute to this defect. Blood contains a percentage of iron, and,
with other extraneous matters, should be washed from the hides before
salting them.
Fortunately, chemists have lately paid attention to the advantages
of the use of pure salt in various industries, with the result that
at least two chemically pure products are now available. The use of
these salts should be general for the cure of hides and skins, as
they are quite dry, and, therefore, easily spread. As a curing agent,
they are much more effective and lasting than common salt.
The use of glauber salts (Na_{2} SO_{4}) is recommended by the
International Commission for the Preservation, Cure, and Disinfection
of Hides and Skins instead of ordinary salt, where the latter is
unobtainable. The preparation of a sterilised salt, however, renders
its export a practical proposition to almost any part of the world.
Although the loss due to bad curing and flaying is very great, it is
quite small compared with the damage caused by natural defects.
The ravages of disease cause a great wastage of hides and skins, as
animals infected with anthrax are immediately destroyed and cremated
in all civilised countries, while, in Great Britain, foot-and-mouth
disease is kept in check by the same drastic method. In many other
countries, the infected cattle are isolated, treated with an
antiseptic hoof-and-mouth wash and generally cured, as it is a mild
fever which soon runs its course, although it is very contagious. The
germ of foot-and-mouth disease has not yet been discovered, for the
most powerful microscope fails to reveal its presence, but cattle
readily show the complaint, as their hoofs and mouths become covered
with swollen lesions.
Another kind of fever, known as "tick," was prevalent in the southern
part of the United States, but this disease was eventually eliminated
by systematically "dipping" the cattle three or four times a year.
The cattle "dip" used effectually prevented the ravages of the fly
which caused the disease. A similar method has of late years been
adopted in South Africa, with the result that cattle-raising in that
country is developing rapidly.
Anthrax is due to the presence of _bacillus anthracis_, a vegetable
organism of Siberian origin. Dry Chinese and Russian hides are
specially liable to contain the spores of anthrax, and, as the
disease proves fatal to workmen infected by it unless treatment with
anti-anthrax serum be given in the early stages, hides and skins
from infected areas should be disinfected before shipment. The method
proposed by Mr. A. Seymour-Jones, which consists in treating hides
with very dilute formic acid and one part of bichloride of mercury
in 1,000 of water, and afterwards with a saturated solution of salt
solution (.02 per cent.) of bichloride of mercury, seems to be the
most effective without damaging the hides.
[Illustration: WARBLE FLY
(1) Egg, (2) Larva, (3 and 4) Chrysalides, (5) Natural form of
fly, (6) Magnified fly.]
A peculiar natural defect is found in many South American goat skins,
especially the Brazilian, which are often badly scratched by the
animals rubbing themselves against cactus plants. Although, perhaps,
more of an artificial than a natural defect, the scratches caused by
cattle rubbing their hides against barbed wire constitute a serious,
but easily avoidable, loss. Such a barbarous system of fencing ought
never to be used.
[Illustration: A KIP CONTAINING 584 HOLES CAUSED BY THE WARBLE FLY
(The skin belongs to W. D. Mark & Sons, Hide Factors,
Newcastle.)]
[Illustration: FIG. 3
HOLE IN COW HIDE, MADE BY THE GRUB OF THE WARBLE FLY
(Magnified fifteen times)]
The most serious loss in connection with hides and skins, however,
is caused by the warble flies, _hypoderma bovis_ and _hypoderma
lineatum_, which lay their eggs on the hides of cattle. It has been a
debatable point for some years as to whether these eggs hatched and
burrowed their way into the hides from the exterior or were licked
and swallowed by the cattle and, after traversing the digestive
tract, pierced the hide from the interior. Professor Carpenter,
who has been experimenting a number of years for the Department
of Agriculture for Ireland, has succeeded in taking a remarkable
photograph (Fig. 3) which proves that the larvae penetrate the hide
from the exterior. These develop within the hide and often penetrate
to the flesh before they fall out to the ground and change into the
fly.
The most effective way of getting rid of the pest is to destroy the
larvae, either by cutting them out and crushing them under foot, or
by piercing them with a hot needle. No satisfactory dressing has
yet been found, but Prof. Carpenter states that sulphur dioxide is
effectual, if a good method of applying it can be devised.
While sheep skins are immune from the attacks of the warble fly, they
are often damaged by the blow-fly, lice, keds, and ticks; by scab
caused by the action of a mite or acarus; and by "cockle," which
causes a wrinkled grain. The origin of cockle is not definitely
known, but it is a seasonal defect which begins to show on a large
number of skins in December and does not disappear until the sheep
are shorn in the following spring.