CUTANEOUS VACCINE FOR FOWL POX 237 



used in all the experiments described in this bulletin. It contained 200 mgm. 

 of powdered pox virus suspended in 50 cc. of sterile 40 per cent glycerol- 

 physiologicaJ saline solutiotn. Phenol was not added to the vaccine and the 

 preparation was not attenuated by heat. The virus varied in age from six 

 weeks to seven months and it consistently produced definite lesions of fowl 

 pox in from four to seven days, or sooner, after its inoculation on the combs 

 of birds of the same age as those which were to be vaccinated. 



The site selected for vaccination was on the outside of either leg just 

 a!bo\e the "hock" joint (tibio-femoral articulation). An area of approxi- 

 mately one square inch was denuded of feathers at this point. If the feathers 

 were plucked from a point higher on the leg there was danger of tearing 

 the skin. The vaccine was then rubbed into the open follicles with a small 

 camel's hair brush which had been cut dovra to about one-fourth of an inch 

 from its quill insertion, in order to give it a necessary stiifness. Not less 

 than three and not more than seven to ten follicles were vaccinated. The 

 immunity which followed a "take" involving but a few follicles appeared to 

 be as complete as when more follicles were concerned. Very little of the 

 vaccine was used, it being the purpose to have the vaccinated area as dry 

 as possible when the bird was released. 



In denuding the area it wasi found preferable to pull the feathers in a 

 direction parallel to their insertion in the follicles and not at right angles 

 to this direction. In other words, the feathers should be pulled downward 

 and not upward toward the back of the bird. This prevents hemorrhage 

 from the small blood vessels at the base of the dermic papillae. The suf- 

 fusion of blood into the follicles had a tendency to flush out or prevent the 

 deposition and retention of vaecine in the open follicles. The feathers are 

 ustually pulled in the reverse direction because of its ease as compared to 

 the preferred method. 



In the earlier eftcperiments (3) a cotton swab attached to a wooden 

 applicator was used to brush the vaccine into the open follicles. It was 

 very satisfactory, but had to be replaced after having been used on from 

 15 to 25 birds. When the camel's hair brush was suggested by Johnson (2) 

 it was adopted and has been used since almost exclusively. However, the 

 ordinary brush must be reenforced before being used. The quill of the 

 brush is softened by soaking it in water'for a few minutes and a small, taper- 

 ing glass rod or piece of glass tubing is forced down into the quill without 

 splitting it until it comes in contact with the hairs of the brush. When the 

 quill hardens, the rod or tubing will be held firmly in place and prevent the 

 hairs of the brush from pushing up into the quill when being used. A brush 

 so reenforced can be used on several hundred birds. The brushes are kept 

 in 2.5 per cent phenol when not in use and just before using are washed in 

 sterile physiological saline solution. 



In the routine vaccination of a nimiber of birds it wa5 found desirable 

 to have plenty of vaccine on hand. Two or three cubic centimeters were 

 poured from the stock container (50 cc. vaccine bottle) into a sterile Stender 

 dish. Any similar piece of glassware may be used. This quantity was suf- 

 ficient to vaccinate approximately 100 birds, but it was discarded after hav- 

 ing been used on from 35 to 50 birds because it became too adulterated with 

 epithelial debris and an exudate of mucous consistency from the follicles and 

 the inferior umbilicus of the feather quills. The Stender dish and its conr- 

 tents were discarded into a beaker of disinfectant. A second sterile Stender 



