316 DISEASES OF CATTLE. 



the body. This tumor is often found in places exposed to trauma- 

 tisms and at seats of scars, or of irritations from pressure and 

 inflammation. 



Treatment. — Treatment should consist in early and complete removal 

 by the knife, including one-half or three-quarters of an inch of the 

 sound tissue adjoining the tumor. If there is a possibility that sarco- 

 matous tissue still remains, either cauterize the wound with a hot 

 iron or powder the walls of the cavity with arsenious acid. 



CANCEE (CARCINOMA). 



Cancers are tumors of epithelial tissues and are malignant. There 

 are several varieties of cancers, §uch as hard, soft, and colloid, but 

 only those growing on the surface will be mentioned here. These 

 malignant tumors of the superficial organs develop primarily from 

 the epidermis or from the glands of the skin. They appear second- 

 arily as spreading infections fpom milk glands, thyroids, anal glands, 

 or as embolisms. In such cases their sole character depends wholly 

 upon the kind of cancer from which they have sprung. The infil- 

 trating cancer begins as an elevation of the skin, which progresses 

 until it becomes rough and nodular. The surface later becomes 

 attacked and an ulcer results, whose edges are outlined by a hard 

 firm zone. 



The ulcerations may remain limited by cicatricial tissue, but it is 

 more likely that the infiltration and destruction of tissue will spread 

 out wider and deeper until a rodent ulcer (so called) is formed. One 

 of the most frequent sites of cancer in cattle is in the eye, where 

 they are called fungus hematodes, but they also occur on the skin, 

 on the genitals, in the stomach, and within the organs. 



Fungus hematodes. — This starts at the inner corner of the eje as a 

 papillary elevation or as small nodules which become fused. They 

 grow larger and become papillomatous, with superficial ulcerations 

 and a tendency toward hemorrhage. In some cases the eye is dis- 

 placed by the growing tumor or is attacked by the cancer cells and 

 entirely destroyed. 



Cancerous growths upon the external genitals and the anus usually 

 present a rough, irregular surface from which there is a constant 

 sloughing of decomposed tissue accompanied by a penetrating, disa- 

 greeable odor. 



The diagnosis of cancer may be made clinically by noting the simul- 

 taneous infection of the lymph glands which .surrou'ud the primary 

 lesion. Deeply burrowing and infiltrating forms which appear as 

 lumps and ulcerations cause marked disfiguration of the affected part. 

 The surface becomes a soft, greasy mass; later it cracks open and 

 from the fissures blood-colored pus exudes, being continually formed 

 by the moist degeneration of the tissues beneath. At first the general 

 health of the animal does not appear affeeted, but later the cancer 



