214 TECHNICAL BULLETIN U 



Standardization of The Cutaneous Vaccine. 



Tlie powdered pox virus used in tlie al)ove ex})erinieiits, wlien Mpjjlied to 

 the scarified areas of the comb and wattles, always produced pronounced 

 lesions of contagious epithelioma in susceptil)le l)irds, within four to seven 

 days after the inoculation. The virus, tiierefore, had an inculcation period 

 of from four to seven days. This variance of three days depended on tiie age 

 of the bird inoculated, or in otiier words on tiie individual resistance of the 

 birds to the virus, and on the age of the virus at tlie time it was used, ^'irus 

 over one year of age was eliminated. 



By varying the virus content of the cutaneous vaccine it was determined 

 that less than 200 milligrams per 50 cc. of 40 per cent glycerol-physiological 

 saline solution failed to produce local vaccine reactions in all trials, while 

 more than this quantity of virus caused a more pronounced generalized reac- 

 tion. It was demonstrated in Experiment 5 that the vaccine became attenu- 

 ated in some manner to such an extent that it failed to produce a complete 

 immunity when more than 25 days old. 



Based on this information, a tentative standard has been adopted for the 

 vaccine, until such time as it may be improved upon. The virus should be 

 less than one year old and produce definite lesions of contagious epithelioma 

 in from four to seven days after inoculation. The cutaneous vaccine should 

 contain 200 milligrams of such a virus suspended in 50 cc. of a tO per cent 

 glycerol-physiological saline solution. It should not be attenuated by heating. 

 It should be used within 25 days after manufacture, preferably within 10 to 

 15 days. When continuous ice-box storage is not available, 0.5 per cent phenol 

 may be added to the suspension. 



Discussion. 



It is apparent, from the residts of the fi^regoing experiments, that local or 

 cutaneous vaccination of an area of bared feather follicles, with the proper 

 virus suspension or vaccine, results in the production of a local pox-eruption 

 and the development of a complete immunity. 



The theory of cutaneous immunity in relation to contagious epithelioma is 

 comparatively new. ^'erge (11) refers to it as a "cuti-immunity" and states 

 that it can be obtained by cuti-vaccination. The experimental evidence in 

 this paper confirms this statement. Verge used 1/10 to 1/20 cc. of his cuta- 

 neous vaccine injected intracutaneously into the wattle. He furtlier states 

 that "the general inuinmity is in reality only an innnunity of the ectoderm", 

 and claims "that the protection in the cutaneoiis and nuicous membranes 

 isolates the structures remaining sensil)le and thus creates a refractory state 

 that extends to the whole body". 



It will be recalled that while producing "imnume" serum for serological 

 study the subcutaneous administration of a triple strength vaccine produced 

 a complete imnumity in all cases where scablike lesions containing pox virus 

 develoj)ed at the point of inoculation. In many of these cases pox nodules 

 also appeared on the comb. It was csideiit that the skin was actively con- 

 cerned in the immunitj' jiroduction. Beach (12) has made similar observa- 

 tions. He used subcutaneous injections of vaccines containing lesion tissues 

 froni fowls a fleeted with the disease and noted that the percentage of birds 

 immunized thereby was higher among those that developed scab lesions at 

 the point of inoculation. He, likewise, found these scab lesions to ccmtain 

 pox virus. The evidence is convincing. In order to [produce a uniform, con- 



