582 CLINICAL VETERINARY MEDICINE AND SURGERY. 



Harvey) ; bladder (Martin and Stolz) ; prostate (Cadiot) ; and other 

 parts of the genital apparatus. We have already mentioned the 

 frequency of new growths in the testicle. Cases have also been seen 

 of cancer of the penis, of the sheath, and of the ovary (Kriiger) ; uterus 

 (Giirlt, Lucet), and vulva (Martin). Contrary to the experience of 

 human surgeons, cancer of the uterus is, in animals, extremely rare. 



Among the other organs affected we may mention the parotid 

 (Laugeron and Cadiot) ; pituitary gland (Mollereau) ; thyroid gland 

 (Cadiot) ; the lung and maxillaries (Leisering, Barrier, Cadiot) ; neck 

 (Miiller) ; tail (Miiller, McFadyean). We have several times seen 

 cancer of the eye in the horse and dog. Mauri saw pulmonary 

 cancer with secondary growths, in the ox. 



Visceral cancers are much rarer than was formerly believed. In a 

 great number of cases the growths found in the thoracic or abdominal 

 viscera, are due to tuberculosis. This mistake has long been made in 

 connection with the dog, for in this animal tuberculosis often produces 

 large growths which invade the viscera, especially the liver and lungs, 

 or the serous membranes, particularly the peritoneum and pleura. 

 The mistake may not be discovered even on histological examina- 

 tion, because the structure of the growth rather recalls sarcoma or 

 lymphadenoma than tubercle. Only the detection of bacilli and the 

 results of inoculation reveal the true nature of these growths. The 

 same remarks apply to the horse. Many cases regarded as lymph- 

 adenoma or visceral tumours are really due to tubercle. 



Growths produced by vegetable parasites have long been mistaken 

 for cancer, and especially for sarcoma. Among such are bovine 

 actinomycosis and equine bothryomycosis, both of which, however, 

 are well known and readily diagnosed at the present day. 



It v/ould almost seem that acari may excite the development of 

 new growths. In an old bitch suffering from tumours of the vulva, 

 which had deformed the vagina and at certain points had perforated 

 its walls, microscopic examination showed the new growths to be 

 formed of round cells, amidst which acari were discovered. 



To sum up, animals may show lesions resembling tumours, which, 

 however, have been produced by the most varied processes, some 

 tuberculous in character, others due to vegetable parasites, like actino- 

 mycoses and bothryomycoses, or to animal parasites, like acari ; others, 

 again, of an ulcerous nature resulting from the action of microbes, like 

 canchroid of the lip in the cat. 



Most of the older writers having failed to sufficiently guard against 

 these causes of error, it is difficult to draw conclusions from their 

 reports. Confusion has occurred even in recent experiments, a fact 



