BACTERIAL INOCULATION 269 



sores of othei-wise healthy individuals, were utilized. 

 Later experiments on calves showed that smallpox 

 virus can be converted into vaccine virus by passage 

 through several (four) generations of the bovine 

 species. Thus the virus is rid of any possible con- 

 tamination from human sources and can be and is pre- 

 pared in any desired quantities. The best vaccine 

 virus is glycerinized and a number of reliable pharma- 

 ceutical firms market the lymph in sealed capillary 

 glass tubes, protected vaccine points and vials. The 

 virus must be preserved in a refrigerator. 



Technic of Vaccination, — The skin of the arm pref- 

 erably or the leg is cleansed with alcohol or ether. 

 The superficial layer of the epidermis is denuded by 

 a sterile von Pirquet scarifier or sharp dental chisel 

 by a rotary motion, or in the absence of these by a 

 scalpel or needle, producing an area about two milli- 

 metres in diameter, caution being observed to draw 

 only serum, not blood. The scarification may be done 

 through a drop of virus primarily placed on the skin 

 or the virus may be deposited when the denudation is 

 completed and rubbed in with a sterile orange stick 

 or toothpick. If possible the di'op of lymph should 

 be allowed to dry in the air or after fifteen minutes a 

 gauze dressing or vaccine shield may be applied to the 

 inoculated site for protection. The cow-pox wound 

 should be inspected daily for at least fixe days. 



