Part 97

=Cattle.= The causes of laceration and hemorrhage of the spleen are similar to those acting in the horse. Blows with the horns on the left side, crowding through a doorway or gateway, and direct blows of other kinds are charged with its pathogenesis. The friability which attends on leucocythæmia has been noted as a predisposing cause. Calves by reason of their small size and the relative bulk of the spleen are especially liable to rupture by kicks from animals or men.

Much more commonly than in solipeds, rupture of the spleen occurs as a complication of specific microbian diseases like anthrax and Southern cattle fever.

Symptoms. The mature animal assumes the recumbent position, refusing to rise, and dies in a few hours. In calves, life may be prolonged for a few hours longer, and there have been noticed, anorexia, watering of the eyes, accelerated pulse and respiration, arrest of intestinal peristalsis, cold ears, rigid limbs, and moderately full belly (Notz). There should also be tenderness on manipulation or percussion of the left hypochondrium, and until coagulation occurs, fluctuation in the lower part of the abdomen, with pallid mucous membranes and other signs of profuse internal hæmorrhage.

Treatment is useless in the majority of cases. In the slighter forms it would be the same as in the horse.

TUMORS OF THE SPLEEN.

Secondary. Delay of blood favors. Sarcoma: horse, cattle, dog. Carcinoma: horse, dog. Melanoma: common and large in gray and white horses, rupture, external melanosis. Angioma: horse, ox. Lymphadenoma: horse, ox, external adenoma.

The different tumors of the spleen are usually secondary. The intimate structure of the organ, the peculiarity of the circulation through the pulp cavities, and the delay of the blood in the pulp spaces, predispose it in a very especial manner to the growth of neoplasms, the germs or bioplasts of which are carried in the blood.

=Sarcoma.= In the horse sarcomata have been found in the spleen secondary to similar tumors in the other parts of the abdominal and thoracic cavities. They may attain to any size, from a pea to the closed fist and, in exceptional cases, of a mass which practically fills and distends the abdominal cavity.

In the cow an encephaloid sarcoma in the spleen, weighed nine pounds and was associated with similar formations in the lymph glands generally of the abdomen and chest.

In the dog also sarcomata are common in the spleen.

=Carcinoma.= These are found in the horse in connection with similar primary tumors, as in the case of the sarcomata. They are at times extremely vascular and soft, and at other times they are hard and fibrous (scirrhus).

In the dog secondary cancer of the spleen is comparatively common.

=Melanoma.= Black pigment tumors are especially common in gray and white horses. Their common seat is on the black, hairless portions of the skin (anus, vulva, perineum, tail, sheath, mamma, eyelids, lips, etc.), and secondarily in the lymph glands and spleen. In the latter they may grow to an extreme size, Wehenkel having mentioned one specimen of 60 pounds. Its surface is marked by uneven, rounded black swellings, the entire organ, indeed, seeming to be a conglomerate of these masses. The intimate structure is that of a sarcoma, so abundantly charged with black pigment granules that these appear to make up the greater part of the mass.

Rupture of these neoplasms with the escape into the abdomen of blood highly charged with the melanic matter is not uncommon.

The symptoms of the splenic deposits are not usually recognizable, but indications of chronic abdominal disease in connection with external melanotic formations may well lead to a reasonable suspicion.

Angioma. In a horse’s spleen weighing 30 lbs., there were numerous soft nodules of a deep cherry color. These were cavernous masses with connective tissue walls and the meshes filled with blood.

Similar vascular cavernous tumors have been found in the cow.

Lymphadenoma has been found in the spleen of horses and cattle in connection with the same disease of the lymph glands.

Like the other splenic tumors this is obscure and usually only found after death. The existence of adenoid swellings elsewhere conjoined with excess of white globules and indications of abdominal pain would be suggestive of splenic disease.

AMYLOID DEGENERATION OF THE SPLEEN.

Amyloid: horse: with exhausting diseases. Waxy secretion staining mahogany brown with iodine. Gangrene: Swine. Tubercle and glander nodules.

This has been occasionally detected in the spleen of the horse. It is usually connected with longstanding suppuration especially of bones, with advanced tuberculosis or other exhausting disease. The organ is usually greatly enlarged and the affected parts are firm, resistant and swollen. On section it has not the soft friable or pulpy appearance of the spleen, but an uniform waxy looking consistency, grayish or sometimes stained with blood. On the application of a solution of iodine and iodide of potassium the healthy splenic tissue is colored yellow, while the amyloid portion becomes of a deep mahogany brown.

GANGRENE OF THE SPLEEN IN SWINE.

Hertzen records the case of a pig in which the spleen had become gangrenous and lay free in a surrounding fibrous capsule.

TUBERCLES AND GLANDERS NODULES OF THE SPLEEN.

Tubercles in the spleen are common in cattle, swine, guinea-pigs, rabbits and cats, in the last largely as the result of ingestion of tuberculous meat. In the larger mammals individual tubercles are usually of the size of a walnut and upward, while in the smaller they show as miliary deposits. The products are often caseated or calcified.

Glander nodules are found in the spleen of the horse and other solipeds and as the result of inoculation in that of rabbits and guinea-pigs. In solipeds they may be of considerable size whereas in the inoculated rodents they are usually small and numerous—like millet seed or pins’ heads.

PARASITES OF THE SPLEEN.