(•()\r Aciors i;i'ri'iii:i.i()M A 215 



sistont, and finu|ilct«' iriiniuiiity tin- .skin must Ix- \ acciiiatcd and a local ])()x 

 reartioM |>r(>diK'ed at the jjoiiit of inoculation. 



Hcsredka's (i;j) ex])Ianatioii of cutaneous ininuinity, as it is produced in 

 several luainnialian diseases, hinges on two propositions, wliich iti the writer's 

 mind are directly applicable to eontajrious epithelioma: 



1. "'I'he susceptibility of the animal is limited principally, if not exclusively, 

 to the cells of the skin. 



2. "The immunity of the animal is due to the vaccination of the reee])tive 

 cells." 



The (piestion naturally arises, how docs this imnmnity s])reatl from a local- 

 ized area on tlie skin to the entire cutaneous surface? Additional investiga- 

 tion is necessary before the question can be answered. Besredka is inclined 

 to believe that "the immunity is local, but its effect reacts upon the rest of 

 the cutaneous surface, because of the large net of lymphatic vessels interested 

 in the jirocess". AVhatever the explanation may be, it has been demonstrated 

 that the entire cutaneous surface is immune to the virus. 



SUMMARY. 



A triple strength vaccine, containing 30 milligrams of active pox virus per 

 dose, when administered to birds subcutaneously, produced a high degree of 

 imminiity to contagious epithelioma. However, scablike lesions and pox 

 nodvdes developed at the point of inoculation and on the comb and eyelids, 

 respectively, following its administration. These lesions were found to con- 

 tain pox virus. Those birds showing such skin lesions were completely im- 

 nume to the disease, as deteriuined 1)V check inoculation of the comb and 

 wattles with the virus. 



Blood was taken from these and other iiunuine birds for serological study. 

 It was found that from 20 cc. to 2.5 cc. of blood could be safely drawn from 

 the brachial vein of a mature bird in good physical condition without any 

 apparent ill results. 



Complement-fixation reactions varied and on the average were but a two- 

 plus reading. Occasionally, a three-plus serum was found. Precipitin studies 

 were negative. The attemjit to ])roduce a ])assi\e inmiunity was a failure. 

 It was, therefore, concluded that, because of the relatively low concentration 

 of specific antibodies in the sera of immune birds, and the failure to produce 

 a passive nnnnmity, a general immunity was not the sole protective force 

 against contagious epitheliojua. 



The development of lesions containing pox virus at the point of inoculation 

 and on the comb and eyelids after the subcutaneous administration of the 

 triple strength vaccine, which was followed by a complete iiunumity, indi- 

 cated that the skin was actively concerned in the immunity against the disea.se. 



Various vaccines were applied to scarified com!) areas and injected into the 

 barbs of the coiub; also, to scarified areas of denuded feather follicles and 

 interfollicular skin surface on the leg just above the tibio-femoral joint. 

 Unfavorable reactions followed. The vaccines were then applied to the de- 

 nuded feather follicles, without previous scarification or cleansing, by rubbing 

 them directly into the follicles v\ith a cotton swab attaclied to a wooden aji- 

 plicator or a pared down camel's hair l>rush. 



A cutaneous vaccine containing 200 milligrams of virus susj)ended in .50 cc. 

 of a 40 per cent glycerol-physiological saline solution (2 parts glycerol and 3 

 pai-ts saline) always caused a swelling of the feather follicles followed by 

 the development of scabs over the orifices of the follicles. This vaccine 



