coxTAC.iors 1 rriiiKi.ioM.v 2i;j 



the sral) form.itioii at tlu' j>oint of iiioiulation is essential to tlu' jirodiiction 

 of a coiiipletf iinmuiiity. 



In c'onjuiu'tion w itii Exjieriiiieiit .5 a f:rou)i of birds was \ acciiiatod cutaiic- 

 ously witli tlif \at'cine used in that experiment, ilie birds were check inocu- 

 lated with virus for ininiunity determination at various jieriods after the day 

 of vaccination. As near as could be determined from the exyierimental evi- 

 dence in this aroup of birds and the birds of Experiment 5 as well, imnuuiity 

 began to develop on about tlie 20th day after vaccination, when the follicular 

 .scab had reached its maxinuan development, continuing until a (•omi)lete im- 

 nnmity had been produced on or altout the 2f)th to 31st day after vaccination, 

 at which time the follicular scab and swelling had practically disappeared. 



Experiment 6. 



A pen of 100 trapnested, ))edigreed Rhode Island Red pullets at the college 

 poultry plant was used in this exjierunent. The cutaneous vaccine (200 milli- 

 grams virus in 50 cc. of -l-O per cent glycerol-saline solution) was administered 

 to 70 of the birds, the remaining 30 being left as controls. The chief purpose 

 of this experiment was to determine the eflect that the vaccine had on egg 

 production. 



Eighteen days after the vaccination, every one of the 70 vaccinated birds 

 demonstrated a well formed feather follicle reaction with scab formation. 

 Three of them showed one or two pox lesions on the comb. It was question- 

 able whether the lesions on the comb were due to generalization of the virus 

 in the vaccine or the result of contact infection. Presumably, they were due 

 to generalization of tlie virus for such lesions were not found in any birds of 

 the control group. 



A close comparison of the trap nest egg records of the control and vacci- 

 nated groups for one month prior to vaccination and thereafter for an addi- 

 tional ten wrecks, indicated that the percentage of egg production in the 

 vaccinated group was materially decreased. This drop in egg production 

 liegan 8 days after vaccination, and on the 21st day after vaccination it had 

 reached its lowest point. From then on the production gradually, but slowly, 

 increased to normal. 



Xo opportunity was given to check the immimity production by virus 

 inoculation of the comb. 



This experiment demonstrated two important points. First, that the cuta- 

 neous vaccine, without exception, always produced a local pox-eruption of 

 the nature of a follicular .swelling and scab formation, which apparently is 

 essential to the development of a complete immunity. Second, that its admin- 

 istration was followed by a material decrea.se of egg production. 



Complement-Fixation in Relation to Cutaneous Immunity. 



All birds u.sed in Experiments 3, 4 and 5 were bled and the seru obtained 

 for complement-fixation tests prior to the check inoculation of the birds for 

 immunity determination. Prior to subjecting the.se sera to complement-fixa- 

 tion tests, known three-plus sera were u.sed to determine tlie antigenic prop- 

 erties of the antigen to be used. In the actual test of the sera from the 

 cutaneously vaccinated birds, positive and negative sera were used as controls. 



The u.sual reaction was complete hemolysis. In two cases a slight anti- 

 complementary action of the sera occurred. 



The results indicated that complement-fixing antibodies were not concerned 

 in the immunity acquired following cutaneous vaccination. 



