ANNUAL REPORT, 1940 107 



about 23 days. In several instances the tumor had attained a size of 

 more than 20 percent of the body weight of the host. 



Metastasis of the tumor was observed in 51 cases. Metastatic foci of 

 the tumor were found in most of the visceral organs, although they were 

 more commonly noted in the heart, proventriculus, and adrenal glands. 

 In 21 of the cases only a single visceral organ was affected with tumor. 

 One case of diffuse metastasis in the liver, spleen, and bone marrow was 

 noted in the twenty-sixth serial passage of the tumor. Such cases have 

 been encountered frequently in chickens inoculated with material after 

 the forty-fifth passage of the tumor, and the birds die from 9 to 15 days 

 after inoculation. Such a reaction represents a new character of the 

 tumor that has developed due to serial passage. 



Fowl paralysis developed in some birds after implants of the tumor 

 (about 3 percent of those inoculated in the first 30 serial passages). There 

 were eight cases (about 5 percent) of fowl paralysis among 151 uninocu- 

 lated control chickens. The average age when the first symptoms were 

 noted was approximately 72 days in the case of inoculated and 67 days 

 in the case of uninoculated chickens. Therefore, there seems to be no 

 significant association of fowl paralysis with the transmissible lymphoid 

 neoplasm. 



Progress has been made on the study and classification of more than 

 300 cases of spontaneous neoplastic disease in chickens derived from 

 various sources. 



Studies of the antigenic composition of blood cells of chickens, dis- 

 cussed in a previous Annual Report (for Year Ending November 30, 

 1939) have been continued. The results to date may be briefly sum- 

 marized as follows: 



The mating of chickens whose blood cell types were Class I produced 

 progeny with blood cells of the same class. The mating of chickens whose 

 blood cells were of Class II produced progeny with blood cells of the same 

 class. The mating of chickens whose blood cells were Class III produced 

 progeny- with blood cells of Classes I, II, and III in the ratio of approxi- 

 mately 1, 1, and 2, respectively. The mating of chickens in which one sex 

 had Class I blood cells and the other sex had Class II blood cells pro- 

 duced progeny with Class III blood cells. These results lead to the 

 tentative conclusion that the genotype of Class I cells is a combination of 

 two dominant genes (AA); Class II cells, of two recessive genes (aa); 

 and Class III cells, of dominant and recessive genes (Aa). 



WALTHAM FIELD STATION 



(Waltham, Mass.) 



Ray M. Koon, in Charge. 



The members of the research staff of the Waltham Field Station are 

 assigned to the unit by the Departments of Botany, Entomology, Flori- 

 culture, Horticulture, and Vegetable Gardening. Reports of these de- 

 partments give results of investigations conducted at this station. 



Evaluation Gardens. The collection of hardy perennials numbering about 

 2000 species and varieties has proved to be of definite value to commercial 

 nurserymen and the general public. 



