IMMUNITY AND ANTITOXINS 253 



stantiate in some measure the distrust which many of the 

 public have from time to time felt in the vaccine commonly- 

 used in vaccination, hence the new form as above designated. 

 This retains the toxic qualities required for immunity, but 

 is so produced that it possesses in addition three very 

 important advantages ; namely, it is entirely free from 

 extraneous organisms, it is available for a large number of 

 vaccinations, and it retains full activity for eight months. 

 It is prepared as follows : 



A calf, aged three to six months, is kept in quarantine 

 for a week. If then found upon examination to be quite 

 healthy, it is removed to the vaccination station, and the 

 lower part of its abdomen antiseptically cleaned. The 

 animal is now vaccinated upon this sterilised area with 

 glycerinated calf lymph. After five days the part is again 

 thoroughly washed, and the contents of the vesicle, which 

 have of course appeared in the interval, are removed with a 

 sterilised sharp spoon, and transferred to a sterilised bottle. 

 This is now removed to the laboratory, and the exact weight 

 of the material ascertained. A calf thus vaccinated will 

 yield from 18 to 24 grams of vaccine material. This is now 

 thoroughly triturated and mixed with six times its weight 

 of a sterilised solution of 50 per cent, chemically pure 

 glycerine in distilled water. The resulting emulsion is 

 aseptically stored in sealed tubes in a cool place. For four 

 weeks it is carefully examined bacteriologically until the 

 glycerine has absolutely killed any possible germ that may 

 have obtained entrance. When by agar plates it is demon- 

 strably sterile it is ready for distribution. 



Pasteur s Treatment of Rabies, Rabies is a disease affect- 

 ing dogs (in Western Europe) and wolves (in Russia), and 

 can be transmitted to other animals and man, infection being 

 carried by the bite of a rabid animal. It takes two chief 

 forms: (i) furious rabies and (2) paralytic rabies. The 

 former is more common in dogs. The animal becomes rest- 



