MALIGNANT TUMOURS IN ANIMALS. 



587 



individual characteristics of the cells and general arrangement of the 

 cylinders recalled the appearance of normal testicle tissue (Fig. 90). 



In animals cancer not infrequently appears first in the nasal fossae, 

 or in the facial sinuses. Sometimes it originates in the paradental 







Fig. 89.--Ostejid sarcomn of th - mammary gland (bitch). 



epithelial debris and invades the superior maxilla. We have collected 

 three cases of these various localisations in the dog and two in the 

 horse. 



One of the dogs exhibited a lymphadenoma readily recognisable by 

 its reticulated stroma containing small round cells and vessels with 

 normal walls. The two other dogs showed alveolar epitheliomata, in 

 which the stroma was scanty and the cells polyhedral or polymorphic. 



The lesions were very different in the horses ; one horse showed a 



Fig. 90. — Epithelioma of the testicle (dogl. 



globo-cellular sarcoma ; in the other the tumour was more complex, 

 being formed of rounded cells, among which were disposed epithelio- 

 matous tracts. 



