SPECIAL REPORT ON DISEASES OF CATTLE TEXT

affected, but later the cancer nodules spread to important organs and give rise to marasmus and progressive emaciation. Cancer is not a frequent tumor of cows. Frˆhner states that of 75 cases of tumors in cattle which came under his observation 2, or 2.6 per cent, were found to be cancers, while 20, or 26.6 per cent, were sarcomas. _Treatment._--Treatment consists in the early and complete removal of the tumor, taking care to include a wide border of healthy tissue. This has been most successful in such superficial cancers as those of the eye, penis, anus, testicle, vulva, and sheath. If the disease has advanced too far, this treatment may not prove efficacious, owing to the great malignancy of the cancer and its tendency to recur. In such cases the animal may be slaughtered, but the flesh should be used for food only after inspection by a competent veterinarian. CYSTS. Cysts may be true or false tumors and consist of a capsule containing a fluid or semisolid content. Among the most important cysts, which have been briefly referred to in a previous table, the following are probably the most noteworthy, owing to the frequency with which they are found in bovines: SOFTENING CYSTS. Softening cysts, which result from the degenerative liquefaction of normal or diseased tissues, especially of tumors of different kinds, followed by the encapsulation of the fluid. PARASITIC CYSTS. Parasitic or foreign-body cysts, from the inflammatory reaction induced by such parasites as the echinococcus (hydatid cyst) or by the presence of various kinds of foreign bodies. EXTRAVASATION CYSTS. Extravasation cysts, caused by injuries which rupture blood vessels, followed by an increase of fibrous tissue which forms a capsule about the fluid. The hygromata in front of the knee in cattle, so-called tumor of the knee, and serous cysts belong to this variety. HYGROMATA, OR TUMORS OF THE KNEE.--These consist in the simplest form of a collection of serous fluid mixed with fibrin within a distended bursa. The walls surrounding the fluid become firm, smooth, and dense. Outwardly the tumor appears fluctuating, though tense, while the skin which covers it may be normal, denuded of hair, or covered with hard epidermal scales, possibly half an inch in thickness, forming a hard, horny plate. The cavity which contains the fluid may have the dimensions of a hen's egg, an apple, or a child's head. Its walls are formed by the diseased secreting membrane of the bursal sac, and are readily detachable from the subcutis of the skin. Their internal surfaces are often uneven or supplied with projections or tufted growths which support a fibrous network within the tumor. Tumors of the knee may also assume a granular type, as the result of chronic inflammation or following operative or spontaneous evacuation of pus from the part. They are either firmly connected with the skin or are detachable from it, and when laid open disclose a whitish-red, porklike tissue surrounding a central nucleus of pus, or a fistulous tract leading to the outer surface. They are caused by the chronic inflammation which follows the bruises received by cattle in lying down and in rising, or they may be due to falls on uneven, hard ground. _Treatment for hygromata._--When the swelling first appears cold water should be applied, followed later by bandaging with cloths wrung out of warm water. If the swelling is soft, it should be punctured at the lowest point, and afterwards the cavity should be syringed with Lugol's solution. If the tumor is hard and nonfluctuating, a mercurial blister may cause absorption and at the same time prevent further injury to the part by making it more painful, thus sparing it. SEROUS CYSTS.--These swellings are another variety of extravasation cysts, and are caused by such injuries as butting, running against hard objects, and shipping bruises, which are followed by an outpouring of blood and lymph into the tissue spaces. These cysts develop rapidly and may reach the size of a man's head or even larger. They are soft, edematous, and hot at first and contain a serous or blood-tinged fluid. Later, partially organized clots and shreds of a fibrinous nature and of a gelatinous consistence are formed within, and the temperature of the swelling is reduced. They appear on the surface of the body, especially on the belly and flank of cattle. _Treatment of serous cysts._--Treatment consists in opening the cyst at the most dependent point with a sharp knife. The cavity should be washed out twice daily with a 5 per cent solution of carbolic acid, and drainage encouraged by keeping the incision open. DERMOID CYSTS. These cysts have a wall which is almost an exact duplicate of the structure of the skin, and frequently contain epidermal structures, such as hair and teeth, which, in the development of the embryo, have been misplaced. Thus we may find in an ovary or testicle a dermoid cyst, containing a tooth or a ball of hair. Dental cysts are included in the class above. DENTAL CYSTS.--It happens occasionally that the teeth of cattle, instead of developing normally within strong supporting alveolÊ, remain inclosed within a cystic membrane, which assumes a tumorlike character. One tooth may be included alone in the cyst or a number may be inclosed together. However this may be, the malformation progresses, especially if confined to the incisor teeth, until the remaining teeth that began to develop normally are crowded out of position and rendered useless. The tumor may reach the size of a man's fist. It appears to be fleshy and dents upon pressure, but it may also appear on closer examination as though it contained irregular sections of thin bone. The outer surface is always smooth, and no indication of purulence, softening, or scab formation is ever exhibited. Upon being laid open with the knife the tumor is seen to be surrounded by a firm, smooth membrane which limits it completely from the adjoining tissues. It is filled with material which possesses partly edematous, partly fleshy, and partly bony properties. It is supposed that this mass is composed of rudiments of the jawbone or of the alveolar walls which, becoming spongy, lose themselves in the soft, fleshy mass contained within the capsule of the tumor. It occasionally happens that the tumor is hollow and that the cavity extends back into the body of the lower jaw for a considerable distance. Tumors of this kind, being of congenital origin, are very naturally observed most frequently in young cattle, but they may continue to expand for a period of several months after the birth of the calf, even until they become troublesome and unsightly. _Treatment for dental cysts._--Treatment consists in the complete extirpation of the cyst and the destruction of the lining pouch by curetting. RETENTION CYSTS. Retention cysts arise from the retention of normal secretions, owing to obstruction of a duct leading from a gland. The mucous cysts found in the mouth, udder, and vestibule of cows are samples of this form. MUCOUS CYSTS.--Saclike dependent tumors, caused by retention of the secretions from the mucous glands, sometimes develop in the mouth, nose, pharynx, and vulva of cattle. They are called "mucous cysts." These are of sizes varying from peas to pigeon eggs, are roundish and translucent, and surrounded by a delicate, vascular membrane. They contain a siruplike substance more or less thick and transparent and whitish yellow in color. Treatment consists in the puncturing of the swelling, if accessible, and the destruction of the cyst walls by the injection of Lugol's solution. PROLIFERATION CYSTS. These are found especially in the ovaries of cows, called "cystic ovaries," and may produce nymphomania (chronic bulling). The treatment indicated in this case is the removal of the diseased ovaries. FOOTNOTES: [3] The term "tumor" literally means a swelling, and thus has been applied to the prominence caused by an overdistended bladder, to the enlargement of pregnancy, to the swelling produced by an abscess, to the overgrowth of tissue (hyperplasia) associated with injury and consequent inflammation, and to numerous other phases of tissue enlargement directly connected with recognized disease processes. For this reason it is becoming more common for scientists to apply the word "neoplasm" to the new growths described in this chapter. Because of the still popular use of the word "tumor," it is retained in this chapter for the designation of those new growths to which the sevenfold characterization of our descriptive definition applies. DISEASES OF THE SKIN. By M. R. TRUMBOWER, D. V. S. [Revised by John R. Mohler, V. M. D.] GENERAL DISCUSSION. The skin consists of two parts--a superficial layer, the epidermis, or cuticle, and the deep, or true, skin, the dermis, cutis vera, or corium. The epidermis, cuticle, or scarf skin, is an epithelial structure, forming a protective covering to the corium. It varies in thickness, is quite insensible and nonvascular, and consists of a sheet of cells. The epidermis is divided into a firm and transparent superficial and a deep, soft layer. The latter is the rete mucosum, whose cells contain the pigment which gives color to the skin. The deep surface of the epidermis is accurately molded on the papillary layer of the true skin, and, when removed by maceration, presents depressions which correspond to the elevations on the dermis. From the cuticle tubular prolongations pass into the sebaceous and sudorific glands; thus the entire surface of the body is inclosed by the cuticle. The dermis, or true skin, is vascular and highly sensitive, containing the tactile ends of the nerves of touch. It is covered by epidermis and attached to the underlying parts by a layer of areolar tissue, which usually contains fat. The cutis consists of a fibro-areolar tissue and vessels of supply. It is divided into two layers, the deep, or true, corium and the upper, or papillary. The corium consists of strong interlacing fibrous bands, chiefly white; its meshes are larger and more open toward the attached surface, giving lodgment to the sweat glands and fat. The papillary, or superficial, layer is formed of a series of small conical eminences or papillÊ, which are highly sensitive, and consists of a homogenous, transparent tissue. The blood vessels form dense capillary plexuses in the corium, terminating by loops in the papillÊ. The papillary nerves run in a waving manner, usually terminating in loops. Hair is an appendage of the skin and forms its external covering. It is a special modification of epidermis, having the same essential structure, and consists of a root, shaft, and point. The root has a bulbous extremity, is lighter and softer than the stem, and is lodged in a recess or hair follicle, which may either be in the corium or subcutaneous areolÊ. The follicle is dilated at the bottom to correspond to the root bulb, and the ducts of one or more sebaceous glands open into it. At the bottom of each follicle is a conical, vascular papilla, similar in every respect to those on the surface of the dermis; this papilla fits into a corresponding depression in the root of the hair. The shaft consists of a center, or medulla, a surrounding fibrous portion, and an external coating, or cortex. The medulla consists of cells containing pigment or fat, is opaque, and deeply colored. All kinds of hair do not have this medulla. The fibrous portion occupies the bulk of the stem, and the cortex is merely a single layer of thin, flat, imbricated (shinglelike) scales. The sebaceous glands, lodged in the corium, are most abundant in parts exposed to friction. They generally open into the hair follicles, occasionally on the surface of the body. Each gland consists of a small duct which terminates in a lobulated recess. These lobules vary, and are, as is the duct, lined with epithelium. They are filled with sebaceous matter which, as it is secreted, is detached into the sacs. They are very plentiful between the claws of cattle. The sudorific glands, or sweat glands, are situated in the subcutaneous areolar tissue, surrounded by a quantity of fat. They are small, round, reddish bodies, each of which consists of one or more fine tubes coiled into a ball, the free end of the tube being continued up through the true skin and cuticle, and opening on the surface. Each sweat gland is supplied with a cluster of capillary blood vessels which vary in size, being very large when perspiration is excessive. The contents of the smaller ones are fluid, and of the larger, semifluid. The skin may be regarded as an organ supplementary in its action to the lungs and kidneys, since by its secretion it is capable of removing a considerable quantity of water from the blood; it also removes small quantities of carbon dioxid, salts, and in certain instances during suppression of the renal secretions a small quantity of urea. The skin is also the chief organ for the regulation of animal heat, by or through conduction, radiation, and evaporation of water, permitting of loss of heat, while it also, through other mechanisms, is able to regulate the heat lost. The hair furnishes protection against extreme and sudden variations of temperature by reason of the fact that hairs are poor conductors of heat, and inclose between them a still layer of air, itself a nonconductor. The hairs are also furnished with an apparatus by which the loss of heat may be regulated; thus, in cold weather, through the contraction of unstriped muscular fibers of the skin, the hairs become erect and the external coat becomes thicker. Cold, too, acts as a stimulus to the growth of hair, and we find, in consequence, a thicker coat in winter than in summer. The hairs also furnish protection against wet, as they are always more or less oily from the secretion of sebaceous glands, and thus shed water. Through their elasticity they furnish mechanical protection, and through the thickness of the coat, to a certain degree, resist the attacks of insects. Finally, the hairs assist the sense of touch. The sweat glands are constantly discharging a watery secretion in the form of insensible perspiration, and by their influence act as regulators of the temperature of the body; hence, in warm weather, the secretion of the skin is increased, which tends to prevent overheating. Sweating, in addition to regulating heat, is also an active agent in removing effete material from the blood; therefore this secretion can not be checked without danger. If the skin is covered with an impermeable coating of grease or tar, death results from blood poisoning, owing to the retention of materials destined to be excreted by the skin. All secretion poured out by the skin is not only modified by the condition of the atmosphere but also by the character and quantity of the food, by the amount of exercise, and especially by the quantity of fluid taken. The sebaceous secretion is intended to lubricate the skin and hairs. It consists of soft, fatty material suspended in water, and is characterized by an odor peculiar to the animal by which it is secreted. I will not attempt to classify the various diseases of the skin, for in a work of this kind it would serve only to confuse the reader. We shall first consider a class of diseases which are of an inflammatory type; next, those caused by faulty secretion and abnormal growth; then, diseases of parasitic origin; lastly, local injuries of the skin. PRURITIS (ITCHING). We shall consider pruritis first as a distinct subject. It is not a disease, only a sensation, and therefore a symptom. It is one of the symptoms accompanying the majority of the diseases which we will consider in this chapter. It is, then, a functional affection produced by slight irritation from without or by an internal cause acting upon the sensory nerves of the skin. Nothing characteristic is seen except the secondary lesions, produced mechanically by scratching or rubbing. There are various forms of itching, the result of specific skin diseases, where the pruritis is a secondary symptom. In such cases it should not be regarded as an independent affection. _Causes._--Many causes may induce the condition which we recognize here as pruritis. The most common one is dirt on the skin, resulting from insufficient care. If the ceiling of the stable is open, so that dust and straw may fall, the skin is irritated and pruritis results. It also occurs in some forms of indigestion. The parts of the body most exposed to this condition are the croup, the back, the top of the neck, and the root of the tail. Another cause is found in affections of the liver and of the kidneys, when an increase of effete material has to be thrown off by the skin. Morbid materials circulating in the blood may produce a tickling or smarting sensation of the skin in their passage from the blood to the free surface of the skin. Certain irritating substances when eaten may be excreted by the skin, and coming thus in direct contact with the sensory nerves produce itching, or may go further and cause distinct inflammation of the skin. In another class of cases the pruritis may be ascribable to an atrophy, contraction, or hardening of the skin, when the nerves become irritated by the pressure. These conditions may be so slightly marked in a thick skin like that of the ox that they can not be recognized. It is frequently noticed that cattle rub themselves as soon as they pass from the stable into the open air--changing from a warm to a cold atmosphere. Again, we may find one that does all its rubbing in the stall. We may look for lice, but fail to find them. These conditions are generally attributable to high feeding and to too close confinement. They may be associated with inflammatory irritation or not; certainly we fail to discover any morbid changes in the skin. There is to some extent a delightful sensation produced by rubbing, and it may partly become a habit of pleasure. _Treatment._--We must place our chief reliance upon a change of food, plenty of exercise, and in most cases the administration of an active cathartic--1 to 1-1/2 pounds of Epsom salt, a handful of common salt, a tablespoonful of ginger or pepper, mixed with 2 quarts of water, all of which is to be given at one dose. Afterwards half an ounce of hyposulphite of soda mixed with the feed may be given twice a day for a week. For an external application, when the skin is abraded or thickened from rubbing, a solution of borax, 4 ounces to the quart of water, may be used. Carbolic acid, 1/2 ounce to a quart of water, will give relief in some cases. INFLAMMATORY DISEASES OF THE SKIN. ERYTHEMA. This is the simplest form of inflammation of the skin. It consists of an increased redness, which may occur in patches or involve considerable surface. The red coloration disappears when pressed by the finger, but soon returns after the pressure is removed. There is seldom much swelling of the affected part, though often there is a glutinous discharge which dries and mats the hair or forms a thin scale upon the skin. In simple erythema the epidermis alone is affected; when it becomes chronic, fissures form and extend into the corium, or true skin. _Causes._--Simple erythema, consisting of an inflammatory irritation, is seen in very young calves, in which the navels leak. The discharge being urine, it causes an irritation of the surrounding skin. Chafing, which is another form of erythema, is occasionally seen on the udders of cows from rubbing by the legs; chafing between the legs is not uncommon among fat steers. Chronic erythema is found in the form of chapped teats of cows and chapped lips in sucking calves. It frequently occurs in cows when they are turned out in winter directly after milking, and in others from chafing by the sucking calf. Some cows are peculiarly subject to sore teats. The