CONTAClIorS Kl'lTHKI.IOMA 203 



Source of Experimental Birds 



M'liitc I.cjiliorii c-ockerels aiul Hliode Island Red jiullets and cockerels were 

 used in the following experiments and were obtained from the ])oiiItry iilant 

 of the Massachusetts Agricultural College. They were progeny of liirds 

 which were free from Salmonella pullorum infection, as determined i)y the 

 agglutination test. The birds were reared on a clean grass range which had 

 not been used for this purpose for three years. At no tune were they siil)- 

 jei'ted to any infectious disease. 



Technic of Bleeding Fowls. 



The pin feathers are plucked from the inner surface of the wing over the 

 triceps region and the area is cleansed with a suitable antiseptic, i)referal)ly 

 alcohol. The brachial vein is selected for l)leeding. It is found sulicutane 

 ously in a nuiscular groove foriued by the bodies of the two major tricep:; 

 nuiscles. A Luer syringe of 10 cc. cai)acity with a 20 gauge needle, li 

 inches long, is used for aspiration. Aseptic precautions are used during the 

 bleeding process. From 20 to 25 cc. of blood can be taken from a mature 

 liird in good physical condition without any apparent ill results. A])])roxi- 

 mately 1.50 birds were bled during the course of this investigation, and an 

 average of 20 cc. of blood was taken from each individual without a single 

 loss. Frequently desirable birds were bled a second and third time at weekly 

 intervals. When more than 10 cc. of blood are required, as was the case in 

 this investigation, a second syringe and the brachial vein of the other wing 

 are used. After bleeding, the needle is removed from the syringe and the 

 blood gently forced into a sterile test tube (6/8 by 6 inches). The tube is 

 .slanted until the l)lood clots, and it is then placed in the ice box over night, 

 during which time the serum separates. 



Source of "Immune" Seruni. 



The first serum subjected to serological study was obtained from \\'hiti' 

 Leghorn cockerels, four to five months of age, which had been used for virus 

 production and had fully recovered from the operation. Later, serum was 

 ol)tained from yearlings that had recovered from either avian diphtheria or 

 bird pox, or both, during their pullet and cockerel year. Serum was also 

 taken from birds while they were in the active stages of contagious epithel- 

 ioma. There was no doubt w-hatever that the first two groups of birds were 

 immune to the disease. One might question the immunity of the yearling 

 group, but this was determined by check inoculation of coml)s with active 

 virus. Lesions of the disease did not appear. If specific antibodies were 

 associated with immunity, they should be found in one or more of these tlirec 

 groups of sera. 



' In addition to tlie above, attemjits were made to produce sera containing 

 S])ecific antibodies by using various vaccine combinations of the active virus. 

 Healthv young White Leghorn cockerels were used in the experiments. It 

 was determined that the .siibcutaneous administration of 30 milligrams of 

 \irus per dose, suspended in a 1-0 per cent glycerol-physiological saline solu- 

 tion, fully ])rotected the birds, in the majority of cases, when they were check 

 inoculated on the comb with virus for imuumity determination. However, 

 scablike lesions, which were found to contain pox virus, invariably appeared 

 at the point of inoculation, and in .several instances pox nodules also aj)- 



