212 TECHNICAL BULLETIN 10 



Pare 13. 



A second group of six heallhy liirds was si'ivcn two injections of a virus C 

 vaccine of 1 cc. each at five clay intervals. The group was divided into lots 

 1, 2, and 3 and inoculated with virus B sixteen, thirty, and forty days re- 

 spectively after Liie second vaccine injection. 



Lot 1. Pox develojied in ten days and persisted in a mild form. 



Lot 2. Pox developed in eight (lays in both birds and avian diphtheria in 

 one bird of the lot. 



Lot 3. Pox developed in eight days, becoming pronounced, and complicated 

 with roup. 



Control: two non-vaccinated, healthy birds inoculated with virus B. Pox 

 developed in eight days and reached a maxiuuun development three days later. 



Part- C. ■ 



\ third group of six healthy birds was given three injections of a virus C 

 vaccine of 1 cc. each at five day intervals. The group was divided into lots 

 1, 2, and 3 and inoculated with virus B fifteen, tliirty, and forty-one days 

 respectively after tlic third vaccine injection. 



Lot \. Pox developed in ten days and persisted in severe form for tliree 

 weeks. 



Lot 2. A slight pox developed in eight days, persisting in a mild form. 



Lot o. Pox developed in eight days, becoming severe and persisting as such. 



Control: two non-vaccinated, liealtiiy birds inoculated with virus B. Pox 

 developed in eiglit days and reached a maximum development four daj's later. 



ResuU. 



One, two, and tliree injections of the vaccine failed to produce an absolute 

 })rotection against artificial infection with heterologous virus B. 



Other vaccine and virus combinations were used, such as a vaccine made of 

 virus B, and its immunizing ability checked with virus C. The results were 

 comparable to experiments 1 and 2. 



Infection by Contact. 



A healthy, young cockerel was added to each lot of the foregoing experi- 

 ments after the disease developed in the supposedly innnune birds. This addi- 

 tion of a strange bird to each lot of birds instigated fights, and minor wounds 

 of the comb followed. This allowed a point of entrance for the virus which 

 contaminated the food, water, and litter. Pox developed in about .50 per cent 

 of those birds in contact with the diseased ones. The infection persisted in a 

 mild form, never reaching the severity evidenced in those birds with which 

 they were in contact. 



Experiment 3. 



An effort was made to determine the curative value of tlie vaccine. A 

 group of vwelve birds was inoculated with virus C. Pox nodules appeared in 

 nine days and a moderate degree of development, which proved to be the maxi- 

 mum, followed in seven days. The group was then divided into two lots of 

 six birds each and placed in separate pens. A virus C vaccine, in a 1 cc. dose 

 was administered to each bird of one lot, the other lot being used as the con- 

 trol. No apparent decrease in number and severity of the pox nodules fol- 

 lowed the injection of the vaccine. The injected lot, however, appeared brig'ht- 

 ev and more' active, and loss of flesh was arrested after seven days following 

 the injection. The non-injected lot steadily lost flesh for two weeks, but from 

 then on gained in general appearance ancl jihysical conditions. 



