CON TACIlorS Kl'irHKl.IO.MA 211 



lurds. l.osions of coiUjijiioiis (■|)itlu-li()iii;i (1<'\ cloix-d, iiulicitiiiir tli.i! the scnlis 

 contaiiu'd tlu' pox virus. 



'I'lu' control leiis of the liirds sliowed no rrat'tioii. 



After complete recovery from the gener.-d elTects of the viiccination (aliont 

 22 days), virus inoculation of tiic comb proved tiiat tiiere was an aj)i)arent 

 imiminity. evidently of a cutaneous nature. Three normal birds were inocu- 

 lated on the comb as controls for the virulence of the \irus used to check the 

 immunity. They all developed a heavy infection. 



K.vfierlnn-iii J. 



Twelve iiirds were used. In this experiment the \accine I'ontained the same 

 amount of \ irus. It was also unatteiuiated, but passed through several layers 

 of sterile gau/e and cotton for the purpose of freeing it of epithelial debri.s, 

 etc. It was injected into each denuded feather follicle, about 1 droj) to each 

 follicle. The })urpose of the injection was to penetrate the dermal ])apilla, 

 not dee])ly, init very su|)erficia!ly. 



The resulting reactions were not conlined to the follicle alone, l)ut sjjread 

 fo the adjacent tissue as well. The systemic reaction was not so pronounced 

 as in the preceding experiment, nor did pox nodides appear on tiie comb and 

 eyelids. Scal)s did apjiear on the orifices of the vaccinated follicles. 



.VU controls were satisfactory and the degree of immunity de\elo])ment, as 

 determined by check virus inoculation, was pronounced. 



J-^.cpi ritiient J. 



Fourteen birds \\ ere used. The vaccine in tiiis case contained but 200 

 milligrams of virus. It was suspended in .50 cc. of a 40 ])er .cent glycerol- 

 lihysiological saline solution, (llycerol was used for the same purpose as in 

 the triple strength vaccine; that is, it was an excellent medium for suspend- 

 ing the virus in solution and it was thought that it might have some attenu- 

 ating action. The vaccine was applied directly to the follicles by rubbing it 

 in well with a cotton swab attached to a wooden ai)pIicator. The area was 

 not previously cleansed nor scarified. The birds reacted to the vaccine in a 

 uniform manner and with but slight variation, as follows: — 



(I. W'itiiin 1 to 8 days aftei' \acciiiation, a gradual swelling of follicles 

 occurred. 



/'. "Within S to IS days after vaccination, a gradual a})pea ranee of follicu- 

 lar scabs occurred. 



r. Within 18 to 31 days after vaccination a gradual disai)i)earance of 

 follicular scabs and swelling occurred, the latter being the last to disai)pear. 



The reactions remained localized. Pox nodides did not appear on the comb. 

 The birds were check inoculated on tiic comb on the 31st day after vaccina- 

 tion with a su.spension of virus. They all showed a complete immunity, while 

 the usual number of controls on the virulence of the virus all presented a 

 heavy comb infection. 



Johnson (9) has reported the experhnental use of such a vacciiu% but 

 found that it caused unfavorable reactions in laying birds and its use was 

 oftentimes attended with mortality. The virus content of his vaccine was 

 slightly higher than that used in Experiment 3. This investigator used a 

 pared down camel's hair brush in applying the vaccine to the feather fol- 

 licles. This method of application has since been u.sed in duplicating ex])eri- 

 ments and found to be both efficient and practicable. Gidlow (10) u.sed the 

 vaccine as recommended by John.son in .several flock trials and rej)orts that 



