March, 1934] Agricultural Research in N. H. 23 



ataxia or muscular incoordination, the result of which is that the chick 

 walks unsteadily. 



Research on this disease has been done cooperatively by the poultry 

 and agricultural chemistry departments of the New Hampshire Experi- 

 ment Station and the department of comparative pathology, Harvard 

 Medical School. Dr. E. Elizabeth Jones represented Harvard. New 

 Hampshire workers were C. A. Bottorff, T. B. Charles, C. L.' Martin, 

 F. D. Reed, A. E. Tepper, and S. R. Shimer. 



The disease has been transferred experimentally to normal chickens 

 by intracerebral inoculations of suspensions of brain and spinal cord of 

 affected birds. During the course of 20 passages the virulence has 

 been increased. 



Attempts to demonstrate the presence of the infective agent in brains 

 of chicken embryos have been inconclusive. 



This disease last year in a group of experimental chicks caused a 

 mortality of from 12 to 57 per cent, varying among the groups. Ef- 

 forts to cause a spread of the disease by contact of the infected and 

 non-affected stock proved futile. It appears the disease is not highly 

 infectious. 



Injections of calcium gluconate, azamine, flavine, and glucose solu- 

 tion were administered. After eight days' treatment the chicks were 

 apparent!}^ in the same condition. 



A series of six hatches involving 32 groups of about 50 chicks each 

 from parents of the chicks which first exhibited the disease showed a 

 high mortality. However, lesions attributable to the disturbance 

 known as epidemic tremor could not be found. 



Pedigree hatching was done in another phase of the investigation. 

 Five successive hatches of eggs produced by the parents w^hose offspring 

 had exhibited the disease, gave great variations in results. Eggs of 

 individual birds varied from zero to 100 per cent hatchability. The 

 livability of chicks varied somewhat. 



Selecting 75 affected pullets and six affected cockerels from the orig- 

 inal diseased stock and combining these with a normal group of males 

 and females, permitted a series of crosses for further study. Five 

 hatches were made during the course of this experiment, and while 

 mortality was high in some groups, in no case were any symptoms 

 noticed nor autopsy diagnosis made of the presence of epidemic trem- 

 or. No significant relationship was discovered between weight of 

 chicks and mortality, or between per cent hatchability within groups, 

 and mortality. 



The data secured do not give foundation for any definite conclu- 

 sions. The crosses involving tremor-affected pullets gave poorest re- 

 sults in livability of chicks, however, but this is undoubtedly due to 

 the poorer physical condition of the parents which resulted in lower 

 vitality in the offspring. 



In an effort to discover any derangement' in the composition of the 

 blood of birds affected by this disease, 15 birds were taken from a hatch 

 where affected chicks were found. They themselves showed no clini- 

 cal symptoms of the disease. From the same lot 15 chicks showing 

 S3''mptoms of the disease were also used. These chicks were 17 weeks 



