MALIGNANT TUMOURS IN ANIMALS. S'St 



the macroscopic appearances of cancer, proved in reality due to tuber- 

 culosis. 



These two cases led us to doubt the old records and those in which 

 the histological or bacteriological characters of the lesions produced 

 have not been carefully studied. We may add, however, that we 

 succeeded in transmitting to dogs papillomatous vegetations developed 

 on the glans penis of an affected dog. The growths thus produced, 

 however, remained local and underwent retrogressive processes, be- 

 having in fact like simple grafts. MM. Duplay and Cazin have 

 related a similar case. 



Negative results do not justify us in denying the parasitic nature of 

 cancer. They simply suggest the need for modifying our experimental 

 methods, for they tend to show that we shall not solve the problem by 

 merely multiplying inoculations by processes hitherto employed. 



Position of the Tumours. — In animals, as in man, cancer may attack 

 the most varied tissues, but shows a well marked predilection for the 

 mammary gland. Of thirty-eight cases observed in dogs eighteen 

 consisted of mammary tumours, a fact which explains the greater 

 frequency of cancer in the bitch. After the mammary gland the 

 testicle is one of the organs most frequently attacked. Retention of 

 this gland within the abdomen seems to predispose it to degenerative 

 new growths. It is not uncommon to find cancerous testicles in 

 monorchid or cryptorchid horses. 



Malignant tumours also occur with some frequency in certain 

 exposed parts and on certain mucous membranes. The nose and 

 sinuses of the face are the seat of various new growths. The same 

 is true of the digestive tract. Cancer of the tongue is exceptional ; 

 that of the lips, though rare in large animals, is fairly frequent in 

 old dogs, in which, however, it must not be confused with a special 

 affection which has long been regarded as of epitheliomatous nature. 

 This so-called canchroid of the lip is oftenest noted in the cat, and 

 has also been seen in the dog ; it is an ulcerative inoculable lesion, 

 but it heals with great facility. On histological examination the growth 

 shows no resemblance to cancer. 



Cases have been published of cancer of the pharynx (Benjamin) ; 

 of .the oesophagus (Lorenz) ; of the stomach in the horse (Roloff, 

 Mouquet, and Cadiot) ; of the pylorus in the dog (Miiller) ; of the 

 rumen (Siedamgrotzky) ; and of the reticulum in the cow (Beylot) ; of 

 the intestine (numerous observations) ; of the anus (Trasbot). Some- 

 times the abdominal viscera are affected, as the pancreas (Nocard, 

 Martin) ; liver (Benjamin and Martin); kidney (Siedamgrotzky, Johne, 



