Comparative Pathology of Lymphocytic Malignancies 165 



It is of interest that Dobberman and Seifried 10 recorded the condemnation 

 for leukemia of from 0.15 to 0.4 per cent of cattle slaughtered in Germany 

 during the years 1927 to 1936. These authors also reported 100 per cent in- 

 crease in the disease in the course of those years, [unack 10 in 1932 expressed 

 an opinion that malignant lymphoma in cattle had doubled in frequenc) 

 during the preceding 25 years. Lockau 10 in 1933 reported finding the disease 

 in 0.0 per cent of 24,000 cattle slaughtered in Berlin. Schottler and 

 Schottler 10 found the disease to affect 10 per cent of the animals in some 

 herds in East Prussia. 



Fig. 13-1. Canine venereal tumor. Large friable tumor mass on the penis of 

 a dog. (AFIP 732552.) 



Dogs 



In the dog several disease entities must be considered by the pathologist 

 in reaching a definitive diagnosis of malignant lymphoma. The most im- 

 portant, and often the most perplexing of these, is the canine venereal 

 tumor. This lesion has been known for many decades and has been the sub- 

 ject of several investigations since the pioneer transmission experiments of 

 Novinsky mentioned previously. The disease is readily transmitted In 

 coitus from infected to susceptible animals and can be experimentally 

 induced by transfer of suspensions of cells from the tumors to normal 

 canine genitalia. The tumors appear on the penis or prepuce of the male 

 and in the vagina and occasionally in the cervix and uterus of the female. 

 Rather large fungoid masses are usually seen (Fig. 13-1) which are friable, 

 richly vascular, and occasionally necrotic. Microscopic examination reveals 

 the tumors to be made up of individually discrete cells with hvperc hromatic 



