586 



CLINICAL VETERINARY MEDICINE AND SURGERY. 



The other case was that of an aged bitch, in which the new growth 

 had existed for two years and had returned after partial ablation. 

 When the animal was killed the mammary gland and lungs were found 

 to contain tumours of cartilaginous appearance, ossified in places. 

 Histological examination showed that the tissue resembled the spongy 

 tissue of bone and contained intercommunicating areolae. The osseous 

 portions were pierced with little angular cavities filled with nucleated 

 cells ; they differed from normal bone inasmuch as there was no 

 lamellar arrangement and no Haversian canals, while the basement 

 substance stained red v.'ith picrocarmine. The areolae surrounded by 



Fig. 88. — Chondroid sarcoma of the mammary gland (bitch.) 



this osteoid tissue contained cells like those in bone marrow 

 (Fig. 89). 



After those of the mammary gland, tumours of the testicle are 

 amongst the most frequent. We have examined five, three from the 

 dog and two from the horse. 



In the horse the tumour may attain considerable size : in one case 

 it weighed four and a half lbs. ; in another affecting a retained testicle 

 the weight was 6 lbs. 10 ozs. 



All five tumours had a very similar appearance. They consisted 

 of a stroma, according to the development of which in various parts 

 t*^^ new growth resembled encephaloid or scirrhous cancer. The 



