Diseases of the Skin 243 



artificial immunity to this disease. Manteufel ^ used a virus 

 obtained by scraping off the softened epitheliomae and 

 macerating these in physiological salt solution. Chickens 

 injected intravenously or subcutaneously with this virus 

 showed an immunity which lasted from one and a half to two 

 years. He also tried a hyperimmune serum but without 

 success. Hadley and Beach ^ report good success with a 

 vaccine prepared in the same way. Their vaccine was pre- 

 pared by grinding pock scabs, diphtheritic membranes, etc., 

 in a sterile mortar with physiological salt solution. This 

 was then filtered through cotton and heated for one hour at 

 55° C. In an infected flock 440 healthy birds were vaccinated 

 with two doses of 1 cc, each at an interval of five days. 

 Only four birds, or less than 1 per cent, in this lot developed 

 noticeable symptoms. Of 75 control birds, 26 cases developed 

 in three weeks. 



Hadley and Beach recommend this vaccine treatment as 

 "especially applicable in large commercial and experimental 

 flocks, where the greatest losses are sustained and where 

 preventative measures can be most economically carried 

 out. Breeders of pure bred and fancy fowls whose stock 

 would be impossible to replace should also find it valuable." 



Prognosis. — The mortality among birds affected with this 

 disease is said to be from 50 to 70 per cent. Gary {loc. cit) 

 says: "I judge this a low per cent of losses if birds are left 

 to themselves without proper care or treatment. But if 

 individual treatment is patiently and regularly applied the 

 mortality can be cut down to less than 20 per cent. If only 

 the skin of the head, and the comb and wattles are involved, 



' Manteufel, Arh. Kaiserl. Gesundheilsamt. Bd. 33, pp. 305-312, 

 1910. 



2 Hadley, F. B., and Beach, B. A., "Controlling Chiekenpox, 

 Sorehead or Contagious Epithelioma by Vaccination." Proc. 

 Amer. Vet. Med. Assoc, Vol. 50, pp. 704-712, 1913. 



