Special Report on Diseases of Cattle Part 17

The specific symptom of b.l.o.o.d.y or smoky water is a very patent one. It may or may not be a.s.sociated with fever, with the presence or absence of abdominal tenderness on pressure, with a very frothy state of the milk or even a reddish tinge, with or without marked paleness of the mucous membranes, and general weakness. When direct injury to the kidneys is the immediate cause of the disease the urine will be pa.s.sed often, in small quant.i.ty at a time, and with much straining. When there is bloodlessness (a watery blood) from insufficient nourishment, fever is absent and the red water is at first the only symptom. When the active cause has been irritant plants, abdominal tenderness, colics, and other signs of bowel inflammation are marked features.

_Treatment._--Treatment varies according as the cause has been a direct irritant operating on a subject in vigorous health or a microbian poison acting on an animal deficient in blood and vigor. In the first form of red water a smart purgative (1 pound to 1-1/2 pounds Glauber's salt) will clear away the irritants from the bowels and allay the coexistent high fever. It will also serve to divert to the bowels much of the irritant products already absorbed into the blood and will thus protect the kidneys. In many such cases a liberal supply of wholesome, easily digestible feed will be all the additional treatment required. In this connection demulcent feed (boiled flaxseed, wheat bran) is especially good. If much blood has been lost, bitters (gentian, one-half ounce) and iron (sulphate of iron, 2 drams) should be given for a week.

For cases in which excess of diuretic plants has been taken, it may be well to replace the salts by 1 to 2 pints of olive oil, adding 1 ounce of laudanum and 2 drams of gum camphor; also to apply fomentations or a fresh sheepskin over the loins. b.u.t.termilk or vinegar, one-half pint, or sulphuric acid, 60 drops in a pint of water, may also be used frequently as injections. In cases caused by sprained or fractured loins, inflamed kidneys, stone or gravel, the treatment will be as for the particular disease in question.

In hematuria from anemia (watery blood), whether from insufficient or badly adjusted rations or from the poisonous products of fermentations in impervious or marshy soils, the treatment must be essentially tonic and stimulating. Rich, abundant, and easily digestible feed must be furnished.

The different grains (oats, barley, wheat, bran, rye) and seeds (rape, linseed, cotton seed) are especially called for and may be given either ground or boiled. As a bitter, sulphate of quinin, one-half dram, and tincture of chlorid of iron, 2 drams, may be given in a pint of water thrice a day. In some cases 1 or 2 teaspoonfuls of oil of turpentine twice daily in milk will act favorably.

In this anemic variety prevention is the great need. The drainage and cultivation of the dangerous soils is the main object. Until this can be accomplished young and newly purchased cattle not yet inured to the poisons must be kept from the dangerous fields and turned on only those which are already drained naturally or artificially. Further, they should have an abundant ration in which the local product of gra.s.s, hay, etc., is supplemented by grain or other seeds. Another point to be guarded against is the supply of water that has drained from marshes or impervious soils, rich in organic matter, as such water is charged with nitrites, ptomaines, etc., which directly conduce to the disorder. Fence out from all such waters and supply from living springs or deep wells only.

ALb.u.mIN IN THE URINE (ALb.u.mINURIA).

In b.l.o.o.d.y urine alb.u.min is always present as an important const.i.tuent of the blood, and in congested and inflamed kidneys it is present as a part of the inflammatory exudate. Apart from these, alb.u.min in the urine represents in different cases a variety of diseased conditions of the kidneys or of distant organs. Among the additional causes of alb.u.minuria may be named: (1) An excess of alb.u.min in the blood (after easy calving with little loss of blood and before the secretion of milk has been established, or in cases of sudden suppression of the secretion of milk); (2) under increase of blood pressure (after deep drinking, after doses of digitalis or broom, after transfusion of blood from one animal to another, or in disease of the heart or lungs causing obstruction to the flow of blood from the veins); (3) after cutting (or disease) of the motor nerves of the vessels going to the kidneys, causing congestion of these organs; (4) violent exertion, hence long drives; the same happens with violent, muscular spasms, as from strychnia poisoning, lockjaw, epilepsy, and convulsions; (5) in most fevers and extensive inflammations of important organs, like the lungs or liver, the escape of the alb.u.min being variously attributed to the high temperature of the body and disorder of the nerves, and to resulting congestion and disorder of the secreting cells of the kidneys; (6) in burns and some other congested states of the skin; (7) under the action of certain poisons (strong acids, phosphorous, a.r.s.enic, Spanish flies, carbolic acid, and those inducing b.l.o.o.d.y urine); (8) in certain conditions of weakness or congestion of the secreting cells of the kidneys, so that they allow this element of the blood to escape; (9) when the feed is entirely wanting in common salt, alb.u.min may appear in the urine temporarily after a full meal containing an excess of alb.u.min. It can also be produced experimentally by puncturing the back part of the base of the brain (the floor of the fourth ventricle close to the point the injury to which causes sugary urine). In abscess, tumor, or inflammation of the bladder, ureter, or urethra the urine is alb.u.minous.

It follows, therefore, that alb.u.min in the urine does not indicate the existence of any one specific disease, and except when from weakness or loss of function of the kidney cells, it must be looked on as an attendant on another disease, the true nature of which we must try to find out. These affections we must exclude one by one until we are left to a.s.sume the noninflammatory disorder of the secreting cells of the kidney. It is especially important to exclude inflammation of the kidney, and to do this may require a microscopic examination of the sediment of the urine and the demonstration of the entire absence of casts of the uriniferous tubes. (See "Nephritis," p. 123.)

To detect alb.u.min in the urine, the suspected and frothy liquid must be rendered sour by adding a few drops of nitric acid and then boiled in a test tube. If a solid precipitate forms, then a few more drops of nitric acid should be added, and if the liquid does not clear it up it is alb.u.min.

A precipitate thrown down by boiling and redissolved by nitric acid is probably phosphate of lime.

_Treatment._--Treatment is usually directed to the disease on which it is dependent. In the absence of any other recognizable disease, mucilaginous drinks of boiled flaxseed, slippery elm, or gum may be given, tannic acid, one-half dram twice daily, and fomentations or even mustard poultices over the loins. When the disease is chronic and there is no attendant fever (elevation of temperature), tonics (hydrochloric acid, 6 drops in a pint of water; phosphate of iron, 2 drams, or sulphate of quinin, 2 drams, repeated twice daily) may be used. In all cases the patient should be kept carefully from cold and wet, a warm, dry shed, or in warm weather a dry, sunny yard or pasture being especially desirable.

SUGAR IN URINE (DIABETES MELLITUS).

This is a frequent condition of the urine in parturition fever, but as a specific disease, a.s.sociated with deranged liver or brain, it is practically unknown in cattle. As a mere attendant on another disease it demands no special notice here.

INFLAMMATION OF THE KIDNEYS (NEPHRITIS).

This has been divided according as it affects the different parts of the kidneys, as: (1) Its fibrous covering (perinephritis); (2) the secreting tissue of its outer portion (parenchymatous); (3) the connective tissue (interst.i.tial); (4) the lining membrane of its ducts (catarrhal); and (5) its pelvis or sac receiving the urine (pyelitis). It has also been distinguished according to the changes that take place in the kidney, especially as seen after death, according to the quant.i.ty of alb.u.min in the urine, and according as the affection is acute or chronic. For the purpose of this work it will be convenient to consider these as one inflammatory disease, making a distinction merely between the acute and the chronic or of long standing.

The _causes_ are in the main like those causing b.l.o.o.d.y urine, such as irritant and diuretic plants, Spanish flies applied as a blister or otherwise, exposure to cold and wet, the presence of stone or gravel in the kidneys, injuries to the back or loins, as by riding one another, the drinking of alkaline or selenitic water, the use of putrid, stagnant water, of that containing bacteria and their products, the consumption of musty fodder, etc. (See "Hematuria," p. 119.)

The length of the loins in cattle predisposes these parts to mechanical injury, and in the lean and especially in the thin, working ox the kidney is very liable to suffer. In the absence of an abundance of loose, connective tissue and of fat, the kidneys lie in close contact with the muscles of the loins, and any injury to them may tend to stretch the kidney and its vessels, or to cause its inflammation by direct extension of the disease from the injured muscle to the adjacent kidney. Thus, under unusually heavy draft, under slips or falls on slippery ground, under sudden unexpected drooping or twisting of the loins from missteps or from the feet sinking into holes, under the loading and jarring of the loins when animals ride one another in cases of "heat," the kidneys are subject to injury and inflammation. A hard run, as when chased by a dog, may be the occasion of such an attack. A fodder rich in nitrogenous or flesh-forming elements (beans, peas, vetches (_Vicia sativa_), and other leguminous plants) has been charged with irritating the kidneys through the excess of urea, hippuric acid, and allied products eliminated through these organs and the tendency to the formation of gravel. It seems, however, that these feeds are most dangerous when partially ripened and yet not fully matured, a stage of growth at which they are liable to contain ingredients irritating to the stomach and poisonous to the brain, as seen in their inducing so-called "stomach staggers." Even in the poisoning by the seeds of ripened but only partially cured rye gra.s.s (_Lolium perenne_), and darnel (_Lolium temulentum_), the kidneys are found violently congested with black blood; also, in the indigestions that result from the eating of partially ripened corn or millet some congestion of the kidneys is an attendant phenomenon.

Cruzel says that the disease as occurring locally is usually not alone from the acrid and resinous plants charged with inducing hematuria, but also from stinking camomile (_Anthemis cotula_) and field poppy when used in the fresh, succulent condition; also from the great prevalence of dead caterpillars on the pasture, or from dead Spanish flies in the stagnant pools of water. The fresh plants are believed to be injurious only by reason of a volatile oil which is dissipated in drying. In the case of the stagnant water it may be questioned whether the chemical products of the contained ferments (bacteria) are not more frequently the cause of the evil than the alleged Spanish flies, though the latter are hurtful enough when present.

Inflammation of the kidneys may further be a form or an extension of a specific contagious disease, such as erysipelas, rinderpest, septicemia, or even of poisoning by the spores of fungi. Rivolta reports the case of a cow with spots of local congestion and blood staining in the kidney, the affected parts being loaded with bacteria. Unfortunately he neither cultivated the bacteria nor inoculated them, and thus the case stands without positive demonstration that they were the cause of disease.

In certain cases the _symptoms_ of nephritis are very manifest, and in others so hidden that the existence of the affection can be certainly recognized only by a microscopic examination of the urine. In violent cases there is high fever, increase of the body temperature to 103 F. and upward; hurried breathing, with a catching inspiration; accelerated pulse; dry, hot muzzle; burning of the roots of the horns and ears; loss of appet.i.te; suspended rumination; and indications of extreme sensitiveness in the loins. The patient stands with back arched and hind legs extended backward and outward, and pa.s.ses water frequently, in driblets, of a high color and specific gravity, containing alb.u.min and microscopic casts. (Pl.

XI, fig. 5.) When made to move, the patient does so with hesitation and groaning, especially if turned in a narrow circle; when pinched on the flank just beneath the lateral bony processes of the loins, especially on that side on which the disease predominates, it flinches and groans. If the examination is made with oiled hand introduced through the last gut (r.e.c.t.u.m), the pressure upward on the kidneys gives rise to great pain and to efforts to escape by moving away and by active contractions of the r.e.c.t.u.m for the expulsion of the hand. Sometimes there is a distinct swelling over the loins or quarter on one or both sides. In uncastrated males the t.e.s.t.i.c.l.e on the affected side is drawn up, or is alternately raised and dropped. In all there is a liability to tremors of the thigh on the side affected.

In some severe cases colicky pains are as violent as in the worst forms of indigestion and spasms of the bowels. The animal frequently shifts from one hind foot to the other, stamps, kicks at the belly, frequently looks anxiously at its flank, moans plaintively, lies down and quickly gets up again, grinds its teeth, twists its tail, and keeps the back habitually arched and rigid and the hind feet advanced under the belly. The bowels may be costive and the feces glistening with a coat of mucus, or they may be loose and irritable, and the paunch or even the bowels may become distended with gas (bloating) as the result of indigestion and fermentation. In some animals, male and female alike, the rigid, arched condition of the back will give way to such undulating movements as are sometimes seen in the act of coition.

The disease does not always appear in its full severity; for a day, or even two, however, there may be merely loss of appet.i.te, impaired rumination, a disposition to remain lying down, yet when the patient is raised it manifests suffering by anxiously looking at the flanks, shifting or stamping of the hind feet, shaking of the tail, and attempts to urinate, which are either fruitless or lead to the discharge of a small quant.i.ty of high-colored or perhaps b.l.o.o.d.y urine.

In some recent slight cases, and in many chronic ones, these symptoms may be absent or un.o.bserved, and an examination of the urine is necessary to reach a safe conclusion. The urine may contain blood, or it may be cloudy from contained alb.u.min, which coagulates on heating with nitric acid (see "Alb.u.minuria," p. 121); it may be slightly glairy from pus, or gritty particles may be detected in it. In seeking for casts of the uriniferous tubes, a drop may be taken with a fine tube from the bottom of the liquid after standing, and examined under a power magnifying 50 diameters. If the fine, cylindroid filaments are seen they may then be examined with a power of 200 or 250 diameters. (Pl. XI, fig. 5.) The appearance of the casts gives some clue to the condition of the kidneys. If made up of large, rounded or slightly columnar cells, with a single nucleus in each cell (epithelial), they imply comparatively slight and recent disease of the kidney tubes, the detachment of the epithelium being like what is seen in any inflamed mucous surface. If made up largely of the small, disk-shaped and nonnucleated red blood globules, they imply escape of blood, and usually a recent injury or congestion of the kidney--it may be from sprains, blows, or the ingestion of acrid or diuretic poisons. If the casts are made of a clear, waxy, h.o.m.ogeneous substance (hyaline), without any admixture of opaque particles, they imply an inflammation of longer standing, in which the inflamed kidney tubules have been already stripped of their cellular (epithelial) lining. If the casts are rendered opaque by the presence of minute, spherical granular cells, like white blood globules, it betokens active suppuration of the kidney tubes. In other cases the casts are rendered opaque by entangled earthy granules (carbonate of lime), or crystals of some other urinary salts. In still other cases the casts entangle clear, refrangent globules of oil or fat, which may imply fatty degeneration of the kidneys or injury to the spinal cord. The presence of free pus giving a glairy, flocculent appearance to the urine is suggestive of inflammation of the urinary pouch at the commencement of the excretory duct (pelvis of kidney) (Pl. IX, fig. 1), especially if complicated with gritty particles of earthy salts. This condition is known as pyelitis. In the chronic cases swelling of the legs or along the lower surface of chest or abdomen, or within these respective cavities, is a common symptom. So, also, stupor or coma, or even convulsions, may supervene from the poisonous action of urea and other waste or morbid products retained in the blood.

_Treatment._--In the treatment of acute nephritis the first consideration is the removal of the cause. Acrid or diuretic plants in the feed must be removed, and what of this kind is present in the stomach or bowels may be cleared away by a moderate dose of castor or olive oil; extensive surfaces of inflammation that have been blistered by Spanish flies must be washed clean with soapsuds; sprains of the back or loins must be treated by soothing fomentations or poultices or by a fresh sheepskin with its fleshy side applied on the loins, and the patient must be kept in a narrow stall in which it can not turn even its head. The patient must be kept in a warm, dry building, so that the skin may be kept active rather than the kidneys.

Warm blanketing is equally important, or even mustard poultices over the loins will be useful. Blisters of Spanish flies, turpentine, or other agent which may be absorbed and irritate the kidneys must be avoided. The active fever may be checked by 15 drops tincture of aconite every four hours or by one-third ounce of acetanilid. If pain is very acute, 1 ounce of laudanum or 2 drams of solid extract of belladonna will serve to relieve. When the severity of the disease has pa.s.sed, a course of tonics (quinin, 2 drams, or gentian powder, 4 drams, daily) may be given. Diuretics, too, may be given cautiously at this advanced stage to relieve dropsy and give tone to the kidneys and general system (oil of turpentine, 2 teaspoonfuls; bicarbonate of soda, 1 teaspoonful, repeated twice a day). Pure water is essential, and it should not be given chilled; warm drinks are preferable.

In the chronic forms of kidney inflammation the same protection against cold and similar general treatment are demanded. Tonics, however, are important to improve the general health (phosphate of iron, 2 drams; powdered nux vomica, 20 grains; powdered gentian root, 4 drams, daily). In some instances the mineral acids (nitric acid, 60 drops, or nitrohydrochloric acid, 60 drops, daily) may be used with the bitters.

Mustard applied to the loins in the form of a thin pulp made with water and covered for an hour with paper or other impervious envelope, or water hotter than the hand can bear, or cupping, may be resorted to as a counterirritant. In cupping, shave the loins, smear them with lard, then take a narrow-mouthed gla.s.s, expand the air within by smearing its interior with a few drops of alcohol, setting it on fire and instantly pressing the mouth of the vessel to the oiled portion of the skin. As the air within the vessel cools it contracts, tending to form a partial vacuum, and the skin, charged with blood, is strongly drawn up within it. Several of these being applied at once, a strong derivation from the affected kidneys is obtained.

In no case of inflamed or irritable kidney should Spanish flies or oil of turpentine be used upon the skin.

PARASITES OF THE KIDNEY.

As the kidney is the visual channel by which the bacteria leave the system, this organ is liable to be implicated when microphytes exist in the blood, and congestions and blood extravasions are produced. In anthrax, southern cattle fever (Texas fever), and other such affections b.l.o.o.d.y urine is the consequence. Of the larger parasites attacking the kidney may be specially named the cystic form of the echinococcus tapeworm of the dog, the cystic form of the unarmed or beef tapeworm of man, the diving bladderworm--the cystic form of the marginate tapeworm of the dog, and the giant strongyle-- the largest of the roundworms. These give rise to general symptoms of kidney disease, but the true source of the trouble is likely to be detected only if the heads or hooklets of the tapeworm or the eggs of the roundworm are found on microscopical examination of the urine.

TUMORS OF THE KIDNEY (HYPERTROPHY OR ATROPHY).

The kidney may be the seat of cancerous or simple tumors, and it may be unnaturally enlarged or reduced in size, but though there may be signs of urinary disorder the true nature of the disease is seldom manifest until after death. The pa.s.sing of blood and of large multi-nucleated cells in the urine (to be detected under the microscope) may betray the existence of an ulcerated cancer of the kidney. The presence of cancerous enlargement of (superficial) lymphatic glands may further a.s.sist and confirm the decision.

RETENTION OF URINE.

Inability to pa.s.s urine may come from any one of three conditions--first, spasm of the neck of the bladder; second, paralysis of the body of the bladder; third, obstruction of the channel of outlet by a stone (calculus) (see Pl. XI) or other obstacle.

In _spasm of the neck of the bladder_ the male animal may stand with the tail slightly raised and making rhythmical contractions of the muscle beneath the a.n.u.s (accelerator urinae) (see Pl. IX, fig. 2), but without pa.s.sing a drop of liquid. In the female the hind legs are extended, widely parted, and the back is arched as if to urinate, but the effort is vain. If the oiled hand is introduced into the r.e.c.t.u.m or v.a.g.i.n.a in the early stages of the affection, the bladder may be felt beneath partially filled, but not overdistended with liquid, and its neck or mouth firm and rigid. In the more advanced stages of the affection the organ is felt as a great, tense, elastic bag, extending forward into the abdomen. In this condition the overdistended muscular coat of the bladder has lost its power of contraction, so that true paralysis has set in, the muscle closing the mouth of the sac alone retaining its contractile power.

In _paralysis of the body of the bladder_ attention is rarely drawn to the urinary disorder until the bladder has been distended to full repletion and is almost ready to give way by rupture and to allow the escape of the contained liquid into the abdomen. Overdistention is the most common cause of the paralysis, yet it may occur from inflammation of the muscular wall of the bladder, or even from injury to the terminal part of the spinal marrow. In this last condition, however, the tail is liable to be powerless, and the neck of the bladder may also be paralyzed, so that the urine dribbles away continuously.

_Causes._--Among the causes of spasm of the neck of the bladder may be named the lodgment of small stones or gravel, the feeding on irritant diuretics (see "b.l.o.o.d.y urine," p. 119, or "Nephritis," p. 123), the enforced retention of urine while at work or during a painful or difficult parturition. The irritation attendant on inflammation of the mucous membrane of the bladder may be a further cause of spasms of the neck, as may also be inflammation of the channel (urethra) back of the neck.

Extensive applications of Spanish flies to the skin, the abuse of diuretics, and the occurrence of indigestion and spasms of the bowels are further causes. So long as spasmodic colic is unrelieved, retention of water from spasm of the neck of the bladder usually persists.

_Treatment._--Treatment depends largely on the cause. In indigestion the irritant contents of the bowels must be got rid of by laxatives and injections of warm water; Spanish-fly blisters must be washed from the surface; a prolonged and too active exertion must be intermitted. The spasm may be relaxed by injecting one-half ounce of solid extract of belladonna in water into the r.e.c.t.u.m or by a solution of tobacco. Chloroform or ether may be given by inhalation, or chloral hydrate (1 ounce) may be given in water by the mouth. Fomentations of warm water may be made over the loins and between the thighs, and the oiled hand inserted into the r.e.c.t.u.m may press moderately on the anterior part of the bladder, which can be felt as an elastic fluctuating bag of an oval shape just beneath.

All other measures failing, the liquid must be drawn off through a tube (catheter). This is, however, exceedingly difficult, alike in male and female, and we can not expect an amateur to succeed in accomplishing it. In the cow the opening into the bladder is found in the median line of the floor of the generative entrance, about 4 inches in front of the external opening, but it is flanked on either side by a blind pouch, into which the catheter will pa.s.s, in ninety-nine cases out of a hundred, in the hands of any but the most skilled operator. In the bull or steer the p.e.n.i.s, when retracted into its sheath, is bent upon itself like the letter S, just above the s.c.r.o.t.u.m and t.e.s.t.i.c.l.es (see Pl. IX, fig. 2), and unless this bend is effaced by extending the organ forward out of its sheath it is quite impossible to pa.s.s a catheter beyond this point. When, however, by the presentation of a female, the animal can be tempted to protrude the p.e.n.i.s, so that it can be seized and extended, or when it can be manipulated forward out of the sheath, it becomes possible to pa.s.s a catheter of small caliber (one-third inch or under) onward into the bladder. Youatt advised laying open the sheath so as to reach and extend the p.e.n.i.s, and others have advocated opening the urethra in the s.p.a.ce between the thighs or just beneath the a.n.u.s, but such formidable operations are beyond the stock owner. The incision of the narrow urethra through the great thickness of muscular and erectile bleeding tissue just beneath the a.n.u.s is especially an operation of extreme delicacy and difficulty. Drawing the liquid through the tube of an aspirator is another possible resort for the professional man. The delicate needle of the aspirator is inserted in such cases through the floor of the v.a.g.i.n.a and upper wall of the bladder in the female, or through the floor of the r.e.c.t.u.m (last gut) and roof of the bladder in the male, or finally through the lower and back part of the abdominal wall, just in front of the bones of the pelvis (pubic bones), thence through the lower and anterior part of the bladder near its blind anterior end. After relief has been obtained the administration of belladonna in 2-dram doses daily for several days will tend to prevent a recurrence of the retention.

When the body of the bladder has become benumbed or paralyzed by overdistention, we may seek to restore its tone by doses of one-half a dram of powdered nux vomica repeated daily, and by mustard plaster applied over the loins, on the back part of the belly inferiorly, or between the thighs.

Small doses (2 drams) of balsam of copaiba are sometimes useful in imparting tone to the partly paralyzed organ.

INCONTINENCE OF URINE (PALSY OF THE NECK OF THE BLADDER).

This may occur from disease or injury to the posterior part of the spinal cord or from broken back, and in these cases the tail, and perhaps the hind limbs, are liable to be paralyzed. In this case the urine dribbles away constantly, and the oiled hand in the v.a.g.i.n.a or r.e.c.t.u.m will feel the half-filled and flaccid bladder beneath and may easily empty it by pressure.

_Treatment._--Treatment is only successful when the cause of the trouble can be remedied. After these (sprains of the back, etc.) have recovered, blisters (mustard) on the loins, the lower part of the abdomen, or between the thighs may be resorted to with success. Two drams of copaiba or of solid extract of belladonna or 2 grains Spanish flies daily may serve to restore the lost tone. These failing, the use of electric currents may still prove successful.

URINARY CALCULI (STONE OR GRAVEL).

Stone or gravel consists of hard bodies mainly made up of the solid earthy const.i.tuents of the urine which have crystallized out of that liquid at some part of the urinary pa.s.sage, and have remained as small particles (gravel), or have concreted into large ma.s.ses (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 pa.s.sages 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 circ.u.mstances, 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 ma.s.ses usually date back to a former period when the animals were restricted to a dry ration.