982 Veteritiary Obstetrics 



Malignant neoplasms of the mammae are very common in the 

 bitch, and exceedingly rare in other domestic animals. In aged 

 bitches mammary carcinoma are very common. They assume 

 various types, most frequently scirrhous, more rarely myxoma- 

 tous, and in some rare cases are accompanied by calcification or 

 ossification. The cancer may break down and result in ulcera- 

 tion, or the blood vessels may become eroded and cause a hematom. 

 The carcinoma usually originate in the substance of the gland, 

 although more rarely they may have their beginning in the skin 

 covering it. As a general rule the development of the tumor is 

 slow, although it may at times be rapid. In some instances the 

 tumors remain quiescent for a long period of time, especially if 

 not interfered with ; while in other cases, especially if the glands 

 have been removed, metastatic tumors occur in the surrounding 

 tissues, which pursue a very rapid and virulent course. 



In carcinoma of the mammae of the bitch, the affected gland 

 or glands are enlarged and hardened. The swelling is distinctly 

 lobular, and usually commences near the base of the teat, extend- 

 ing thence upward to involve the entire gland. Sometimes the 

 disease is confined to a single gland, but frequently it involves 

 several, and in some cases virtually all of the glands, one after 

 another. The extension from one gland to another may be very 

 rapid. 



Sarcoma of the milk glands occur chiefly in the bitch and 

 mare, as nodular and more or less soft swellings, which may reach 

 very large proportions. In the mare the tumor may extend up- 

 ward from the gland through the inguinal canal into the peritoneal 

 cavity. 



As in the adeno-fibrom and the carcinom, so in sarcoma, there 

 may be a tendency to o.ssification, or cysts may form containing 

 a variable quantity of fluid, which ma}- resemble mucus, and con- 

 tain detritis of cells, along with fat and crystals of cholesterine. 



Other tumors of the mammary glands, such as chondroma, 

 lipoma and osteoma, occur in domestic animals, especially in the 

 bitch. Very rarely large cystic tumors form in the mammae, 

 filled with a mucoid substance, while their boundaries may be cal- 

 cified and .sharply limited so that they can be easily enucleated. 



Rehmet relates the occurrence of echinococcus polymorphus in 

 the udder of a cow. Numerous large firm nodules were observed, 

 which were su.spected of being tubercular in character ; but. 



