274 



PHARMACEUTICAL BACTERIOLOGY 



passage through the animal it becomes modified, losing in virulency, 

 yet capable of producing immunity as the result of a mild intoxication 



(vaccinia). 



c. Removing the Scab.— The animal is again fastened to the frame. 



The inoculated surface is washed and dried. The thick scab which has 



' formed over the inoculated area is then removed and triturated with 50 per 



cent, glycerin. This constitutes the small-pox vaccine. 



Fig. 68. — Showing the heifer strapped to the frame, preparatory to removing the 

 vaccinia scab from the area which was scarified and inoculated with the small-pox virus. 

 The scab patches show dark. 



d. Aging or Ripening the Vaccine. — The fresh or raw vaccine is not 

 used as it contains various living microbes. It is acted upon by the 

 glycerin added, for five or six weeks. The virus is tested bacteriologically 

 during this period, and as soon as no more colonies appear it is ready for use. 



e. Preparing for the Market.- — The vaccine is now put into- small glass 

 tubes and marketed as glycerinated tube virus. The vaccine should be 

 kept in a cool, dry place. It deteriorates gradually and the time hmit of 

 usefulness is stamped on each package. 



The old time ivory tips are still on the market and are preferred by' 

 many physicians. A dry bulk form of the virus is also marketed. The 

 manner of the use and the action- of the virus are universally' known. As 



