ANNUAL REPORT, 1933 59 



lymphoc3"toma apparently metastasized into the nervous system, and in other 

 cases the metastasis extended in the opposite direction, i. e., from the nervous 

 system into adjacent tissues. Concurrent affections were ruled out because the 

 tumorous growths appeared to be continuous in these cases. In other cases 

 hmphocytomas and neurolymphomas were found to be sharply separated by 

 parenchymatous organs, muscles, and nervous tissue. The only possible explana- 

 tion of these malignant growths concurrently invading all tissues of the fowl 

 as single entities is that they are either hmphocytomas or neurolymphomas of 

 such invasiveness that all tissues are affected by them. If this explanation is 

 correct, then lyniphoc>toma and neurolymphomatosis have the same pathological 

 characteristics when invading the same tissues; and it follows that neurolympho- 

 matosis is a disease of young birds, while lymphocytoma is a manifestation of 

 the same disease in older birds ten months or more of age. However, in spite 

 of the conclusiveness of the evidence presented by these histological studies of 

 spontaneous cases, the exact relation between lymphocytoma and neurolympho- 

 matosis awaits etiological confirmation. 



In these studies neurolymphomatosis was rarely found associated with a 

 leukemic state of the blood, such as occurs in erythroleukosis and myelogenous 

 leukemia. Lymphocytoma was more often complicated by leukemia. 



Lymphoc\toma, neurolymphomatosis, and leukemia are apparently respon- 

 sible for an excessive mortality in flocks in which they exist, and are quite beyond 

 the power of the average poultryman to control. The object of this study is to 

 find some practical method of control. The results thus far indicate that all of 

 them are probably of an infectious nature and poultrymen may be able to control 

 them by slaughtering all birds showing symptoms. The diagnostic service is 

 available to poultrymen for the purpose of assisting in the diagnosis of these 

 diseases. 



Sexing Living Baby Chicks. (C. S. Gibbs.) A demonstration of sexing living 

 baby chicks was put on at the Poultry Breeders' School this year (1933). Con- 

 siderable interest was shown and the method may find some practical use in 

 New England. Schools are being established on the Pacific Coast and in the 

 Middle West for the determination of sex in living baby chicks, and New Eng- 

 land pountrymen may be forced to sex their chicks in the future in order to hold 

 their trade. Furthermore, it should be remembered that over-production is 

 one of the Nation's greatest problems. Drastic steps are being taken by the more 

 progressive industries under the direction of the government for the curtailment 

 of production of those commodities of which there is a surplus. Chick sexing 

 immediately offers a method of reducing the cockerel surplus and lowering the 

 cost of pullet production, as well as simplifying disease control problems due to 

 overcrowding. 



WALTHAM FIELD STATION 

 (Waltham, Massachusetts) 

 Ray M. Koon in Charge 



For reports on approved projects conducted at this Station, in addition to those 

 listed under this caption, see reports of the Departments of Botany, Entomology, 

 Floriculture, and Olericulture. 



Along with its function as a research unit of the College, this Station has con- 

 tinued to develop and advance in its usefulness as a center of information because 



