COXTACIOrS F.l'l'niKI.IOM A 209 



fiilcrprrtnfiiui. 



riie above results iiiclioatcd tliat the intravenous and sul)Oiitaneoiis admin- 

 istration i>f "immune" serum, for the j)ur]>ose of produeinj>- a j^assive inuiniii- 

 ity, failed to protect tlie l)irds auainst artirK'ial inoculation with the \ii-us of 

 contaji'inus ei)ithelioma. 



Conclusions. 



1. Tlie varyina; and incomplete conn)lement-(ixation reactions of sera froia 

 birds imnnme to contagious epithelioma indicated that the formulation of a 

 unit value of protective antiserum, against which the vaccine or its virus 

 might be standardized, was impossible. 



2. The low degree of specific antibody concentration in the sera of liirds 

 immune to contagious epithelioma and the failure to produce a passive im- 

 munity indicated that a general immunity was not the sole protective force 

 against the disease. 



3. The development of lesions containing the virus of the disease at the 

 point of inoculation and on the comb, after the subcutaneous administration 

 of the triple strength vaccine, which was followed by the production of a 

 complete immunity, indicated that the skin jjrobably plays an important part 

 in the immimity against the disease. 



CUTANEOUS IMMUNITY. 



It appears that there is another inununity factor operating in contagious 

 epithelioma and it is evident that the subcutaneous injection of virus does 

 not consistently produce this factor. 



De Blieck and Van Heelsbergen (4) have apparently solved the problem 

 of immunization against contagious epithelioma in European countries by 

 producing a local or cutaneous immunity. They use a vaccine, known as 

 "Antidiphtherin", which is "a thoroughly living vaccination material, the 

 vitality of which has not been decreased, either physically or chemically, 

 which always gives rise to a local pox-eruption, which never generalizes, which 

 immunizes against the experimental as well as against the spontaneous infec- 

 tion, and which is constant for all these properties during all seasons". The 

 vaccine is applied to an area of denuded feather follicles on the leg by means 

 of a vaccinating instrument or small trocar. A swelling (pox eruption) of 

 the follicles results and the investigators claim that birds showing such local 

 or cutaneous reactions are immune to both the experimental and spontaneous 

 infections. Hoi (5) claims to have had marked success with "Antidiphtherin" 

 in Holland. Doyle (6), in testing out samples of the vaccine procured on 

 the open market, found them to vary in degree of "attenuation", and to 

 cause a generalized infection in several instances. According to De Blieck 

 (7) these faults of the vaccine have since been overcome. 



De Blieck and Van Heelsbergen do not mention their method of ])roducing 

 "Antidiphtherin". Their various publications refer but briefly to a descrip- 

 tion of the general properties of the vaccine and its method of administration. 



Experimental Comb Vaccination. 



The early attempts to produce a local or cutaneous iiiummity (July, 192fi) 



