92 MASS. EXPERIMENT STATION BULLETIN 347 



typhoid were detected on more premises than the previous year. Fowl cholera 

 was identified on eight premises of which six represented new foci of infection, 

 whereas fowl typhoid was diagnosed on four premises all of which represented 

 new foci. Fowl typhoid in turkeys was encountered once. Paratyphoid infection 

 was diagnosed once in chickens and three times in turkeys. From one turkey 

 flock 51 dead embryos were cultured and no paratyphoid was isolated. One case 

 of avian tuberculosis was noted. 



3. Flock Mortality Studies. Morbid and dead specimens were necropsied from 

 two flocks. 



Flock A. Among 765 pullets placed in the laying houses in September, 1936, 

 the mortality was 122 birds (15.95 percent) of which 106 (86.88 percent) were 

 submitted to the laboratory during the first laying year or from September, 1936, 

 to October, 1937. As in former years the peak mortality in this flock was reached 

 from March to July, inclusive, when 62 birds (58.49 percent) were received. 

 Of the 106 birds examined, two were decomposed and no diagnosis was made 

 in 14 (13.21 percent). Twenty-four disease conditions were observed among the 

 specimens submitted. Reproductive disorders 22 (18.33 percent), kidney disorders 

 21 (17.50 percent), cannibalism 14 (1 1.66 percent), and tumors 13 (10.83 percent) 

 represented 58.33 percent of the total diagnoses. 



Flock B. On October 1, 1936, the flock consisted of 6^4 pullets. Examina- 

 tions were started November 1, covering a 13-months period to December 1, 

 1937, and including 308 birds or a mortality of 44.38 percent. The season of peak 

 mortality was longer than in Flock A, extending from February through August, 

 and included 221 birds (71.75 percent). Of the specimens submitted, eight were 

 decomposed and six were recorded as "no diagnosis". A total of 39 disease condi- 

 tions was observed among the specimens. Tumors 80 (21.05 percent), fowl 

 paralysis 59 (15.53 percent), kidney disorders 55 (14.47 percent), reproductive 

 disorders 36 (9.47 percent), cannibalism 14 (3.68 percent), gizzard necrosis 14 

 (3.68 percent), and enterohepatitis 12 (3.16 percent) accounted for 71.05 percent 

 of the total diagnoses. Fowl paralysis and tumors showed a greater incidence 

 in this flock than is usual among birds of this age. The incidence of fowl paralysis 

 continued high until May when the birds were o\er one year of age. The high 

 incidence of tumors began in March when the birds were nearly one year of age 

 and continued during the period of observation. 



4. Erysipelas Outbreaks in Turkeys. Disease outbreaks due to Erysipelothrix 

 rhusiopathiae were obser^•ed in three widely separated turkey flocks at approx- 

 imately the same time of the year. This disease among turkeys has been reported 

 previously only twice in this country'. Affected birds may exhibit very pronounced 

 and striking pathologic changes. Erysipelas infection in adult turkey flocks may- 

 cause serious losses in the form of mortality, retardation in growth, and less 

 profitable marketing of carcasses for food consumption. The results of the field 

 and laboratory studies have been submitted for publication in the Journal of the 

 American Veterinary Medical Association. 



5. ^^ Epidemic Tremor'' in Chicks. During the past year "epidemic tremor" 

 investigations have been continued. Chicks hatched at the laboratory from 

 breeding stock which survived the disease did not exhibit symptoms of "epidemic 

 tremor". The disease was transmitted from spontaneous field cases to experi- 

 mental chicks by means of intracerebral inoculations with saline-brain suspen- 

 sion. The disease-producing agent has been maintained in chicks through 34 

 serial passages. Filtration experiments have demonstrated that the cause of the 

 disease is a filtrable agent. The disease was not transmitted from inoculated 

 infected chicks to uninoculated chicks through cohabitation. Chicks hatched 



