574 DISEASES OF UNKNOWN ETIOLOGY 



which are invariably present in "green vaccine" it does not seriously 

 impair the activity of the virus itself. After one to two months' 

 storage, which is generally practiced to reduce the number of bac- 

 teria, the vaccine is relatively free from microorganisms, although 

 it is practically never sterile. 



The ripened vaccine is subjected to a bacteriological examination 

 to determine the number of bacteria per cubic centimeter, the absence 

 of tetanus bacilli and streptococci, and a guinea-pig inoculation is 

 is made with about a cubic centimeter of it to guard against an acci- 

 dental excess of carbolic acid, before it is tested clinically for its 

 potency. The potency test is made upon several children (previously 

 unvaccinated) in the usual manner. Generally at least a dozen cases 

 are vaccinated and a high percentage of "takes" must be obtained 

 before the product is finally marketed. 



Recently Noguchi 1 has cultivated an absolutely sterile vaccine virus 

 of high potency in the testes of rabbits and bulls. The entire freedom 

 of the preparation from alien microorganisms not only eliminates the 

 necessity of a ripening process to reduce bacterial contamination; 

 it also makes it possible to reduce the cost of production materially. 

 The vaccinal eruption induced in the cornea, skin and testes of rabbits 

 and the skin eruptions in calves were identical with those induced 

 by the virus perpetuated in the ordinary manner. The eruptions 

 induced in man also were perfectly typical. Finally, the sterile tes- 

 ticular vaccine induced immunity reactions in experimental animals 

 identical with those obtained with the ordinary ".skin" vaccine. 



Phenomena of Vaccination. 1. Technic. The site of vaccination, 

 preferably the outer aspect of the arm about the deltoid muscle, is 

 cleansed thoroughly with soap and water, and finally with alcohol 

 if possible. When the surface is dry a light scratch about an inch 

 long is made with a sterile needle, 2 deep enough so that the bottom 

 of the incision is slightly reddened, but not deep enough to draw blood. 

 The virus is then spread over the area and brought into intimate 

 contact with the epidermal layer by gentle rubbing with the side of 

 the needle. The safest method of vaccination is by puncture either 

 with a charged needle, or through a shallow abrasion made with a 

 von Pirquet tuberculin chisel. The chances of successful vaccination 

 by the puncture method are much less than by the linear incision, 

 however. The older method of vaccination was through a scarified 



1 Jour. Exp. Med., 1915, xxi, 539. 



2 An ordinary sewing needle is excellent for the purpose. 



