BIRD POX VACCINES AND BACTERINS 211 



and wattles witli virus B. Pox nodules developed eight days later and readied 

 a niaxiniuin growth in an additional ten days. 



Lot 2. Twenty-six days after vaccination both birds were inoculated on 

 comb and wattles with virus B. A mild pox developed eight days later, but 

 soon disapjieared without further develojjment. 



Lot 3. Forty-two days after vaccination both birds were inoculated on comb 

 and wattles with virus B. Pox was pronounced eight days later, one bird 

 showing diphtheritic patches in mouth as well as pox. 



Control: two non-vaccinated birds inoculated with virus B. Incubation 

 period of eight days, maximum development four days later. 



Part B. 



Two injections of a virus B vaccine were given a second group of six birds 

 in the same manner. The second injection was given six days after the 

 hrst. Ihe group was likewise divided into three lots of two birds each, and 

 inoculated with virus B fifteen, thirty, and forty-two days respectively after 

 tlie second injection. 



Lot 1. Incubation period of ten days, pox becoming pronounced five days 

 later. 



Lot 2. Slight pox developed in eight days in only one bird, clearing up 

 within the next seven days. Second bird showed no evidence of the disease. 



Lot 3. Pox developed in ten days, persisting for three weeks in a mild form. 



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

 developed in eight days, reaching a maximum development four days later. 



Part C. 



Three injections of a virus B vaccine were given a third group of six birds 

 at intervals of six days. The group was again divided into three lots of two 

 birds each, and inoculated with virus B sixteen, thirty-one, and forty-two days 

 respectively after the third injection. 



Lot 1. Pox developed in eleven days and persisted in mild form. 



Lot 2. Pox developed in eight days and became pronounced in anotiier 

 week. 



Lot 3. Pox developed in twelve days and persisted in mild form for tliree 

 weeks. 



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

 developed in eight days, reaching a maximum development three days later. 



Reault. 



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

 protection against artificial infection with homologous virus B. 



Experiment 2. 

 Part A. 



This experiment was similar to Experiment 1, except that the vaccine was 

 made of virus C and the check inoculations were made with virus B. The 

 first group of six birds was given a 1 cc. injection of the vaccine, divided into 

 tliree lots of two birds each, and inoculated with virus B seventeen, twenty- 

 six, and forty days respectively after the vaccine injection. 



Lot 1. Pox developed nine days later, grew worse, and death followed in 

 one bird. 



Lot 2. Pox developed within eight days, but in weak form, and cleared up 

 in two weeks. 



Lot 3. Pox developed within eight days in one bird and diphtheritic roup 

 within len days in the other. 



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

 developed in nine days, reaching a maximum develoi)ment four days later. 



