212 



Part B. 



TECHNICAL BULLETIN 10 



A .second group of six lieallhy birds was given two 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 sixteen, thirty, and forty days re- 

 spectively after the second vaccine injection. 



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



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

 one bird of the lot. 



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

 with roup. 



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

 developed in eight days and reached a maxinuun development tliree days later. 



Part C. 



A 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, thirty, and forty-one days 

 respectively after the third vaccine injection. 



Lot 1. Pox developed in ten days and persisted in severe form for tiiree 

 weeks. 



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



Lot 3. Pox developed in eight days, becoming severe and persisting as such. 



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

 developed in eight days and readied a maxinuim development four days later. 



Result. 



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

 protection against artificial infection witli iieterologous 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 immune 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 

 tliey were in contact. 



Experiment 3. 



An ett'ort was made to determine the curative value of the vaccine. A 

 group of vweive birds was inoculated witli virus C. Pox nodules apjieared in 

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

 mum, followed in seven days. Tlie group was liien divided into two lots of 

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

 was administered to each bird of one lot, tiie 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 bright- 

 er and more active, and lo.ss of flesh was arrested after seven days following 

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

 then on gained in general ajipearance and physical conditions. 



