MANUFACTURE O^ VACCINES 563 



are the most important: smallpox vaccine, blackleg vaccine, rabies 

 vaccine, typhoid vaccine and perhaps Pasteur's anthrax vaccine. 

 The simultaneous method, or injection of hyperimmune serum, to- 

 gether with the specific virus is used in vaccinating against hog- 

 cholera, cattle plague (Rinderpest), anthrax and foot-and-mouth 

 disease. Asiatic cholera, bubonic plague, tuberculosis, acne, pertussis, 

 pneumonia, canine distemper, furunculosis, septicaemia hemorrhagica, 

 gonorrhoea and various inflammatory processes are treated, practically 

 and experimentally, by various methods of vaccination, either as 

 prophylactic or curative measures. 



Smallpox Vaccine. — The first experiments relative to vaccination 

 against smallpox date back to 1796. Prior to that time, the only 

 specific preventive method used in warding off this disease depended 

 upon the inoculation of healthy individuals with smallpox virus from 

 a mild case of the disease. The present method of vaccination util- 

 izes cowpox virus as the protective material. It has not been con- 

 clusively determined that cowpox in cattle and smallpox in man 

 possess intimately related causative factors, but notwithstanding, 

 abundant evidence proves the efficacy of cowpox virus as a specific 

 prophylactic against smallpox in man. ' 



In the practical preparation of smallpox vaccine, the virus or 

 "seed" is first secured by removing the pulp from the vesicles which 

 appear on infected heifers. Most laboratories which engage in this 

 work use a stock mixture of cowpox virus which originated from 

 spontaneous cases of cowpox, and which is known to produce active 

 smallpox vaccine. 



Great care is exercised in the selection and preparation of animals 

 fised in making the vaccine. Heifers (calves or yearlings) are most 

 frequently used in this work, older cattle being employed in a few 

 European laboratories. When first purchased these animals are 

 placed in a detention stable where they are inspected by a qualified 

 veterinarian and carefully tested for tuberculosis. If, after several 

 weeks' quarantine, they are passed as healthy in every way, they 

 are admitted to the vaccine laboratory after their bodies have been 

 scrubbed with soap and water and a weak antiseptic solution. 



The operating room and propagating ward should be constructed 

 with a view to thorough cleanliness. Concrete floors, enameled walls 

 and ceilings and simple sanitary apparatus should characterize the 



