66 MASS. EXPERIMENT STATION BULLETIN 436 



3. Flock Mortality Studies. Necropsies were made on 256 birds (111 females, 

 144 males, 1 unidentified) from the flock hatched in the spring of 1944 and main- 

 tained at the College for genetic studies. In the females, tumors, reproductive 

 disorders, kidney disorders, and fowl paralysis accounted for more than three- 

 fourths of the mortaility. On the basis of gross examination, the tumors were 

 classified as follows: 



Lymphocytoma 11 Leukosis 2 Papilloma 1 



Myelocytoma._ 4 Carcinoma.- 2 Unidentified 1 



Leiomyoma 3 Hemangioma 2 



In males, cannibalism, bacterial and mycotic diseases, kidney disorders, and 

 fowl paralysis were the conditions most frequently encountered, accounting for 

 60 percent of the deaths. 



4. Infectious Bronchitis. During 1945, 228 flocks were enrolled in the in- 

 fectious bronchitis control program, which was carried on in much the same 

 manner as in 1944. Several flocks enrolled in 1944 did not continue the program 

 in 1945 for reasons not reported by the owners. 



The bronchitis problem was greatly complicated by the identification of the 

 Newcastle disease in Massachusetts in November 1945. Since the symptoms 

 and lesions of the two diseases are so similar, an accurate diagnosis is not likely 

 without resorting to refined and tedious laboratory tests. A survey is in progress 

 to determine the distribution and incidence of these two diseases. Investigations 

 into the transmission of the virus have recently shown that the virus of New- 

 castle disease can be isolated from fresh eggs laid by flocks which are in the 

 terminal stages of the disease. The potential and practical significance of this 

 finding is being investigated. When more personnel becomes available, methods 

 of control will also be studied. 



5. Farm Department Brucellosis Control and Eradication. The laboratory 

 tested 388 bovine and 22 porcine blood samples by the standard tube agglutina- 

 tion method during the 1945 calendar year. 



Mastitis Testing Laboratory. The progress in the development of an adequate 

 mastitis testing laboratory has been consistent with delays experienced in all 

 activities where new personnel and equipment are necessary. 



WALTHAM FIELD STATION 

 Waltham, Massachusetts 

 Ray M. Kooii: In Charge 



The members of the research staff of the Waltham Field State are assigned to 

 this branch by the Departments of Botany, Entomology, Floriculture, Horti- 

 culture, and Vegetable Gardening. Refer to reports of these Departments for 

 results of investigations conducted at this Station. 



