SEROLOGY— MANUFACTURE AND USE OF SERA AND VACCINES 275 



now prepared the remedy is absolutely safe. No ill effects ever foUow its 

 use. Of the millions of persons inoculated within recent years, there 

 probably has not been a single instance of b9,d effects which could be 

 traced primarily to the vaccine virus itself. A small-pox vaccination is not 

 nearly as likely to produce ill effects as the customary hand shake. In 

 fact the latter operation does occasionally spread an infection. 



10. Hydrophobia or Rabies Vaccine 



Pasteur's hydrophobia virus is obtained from the spinal cord of rabbits, 

 inoculated with the virus from a dog suffering with rabies. The inocula- 

 tion is made into the dura mater of the spinal cord. The rabbit dies in 

 about two weeks. A second rabbit is inoculated from the first, which dies 

 even sooner, showing that the toxin gained in virulency in its passage 

 through the first animal. This is repeated until finally the animal dies in 

 six or seven days after inoculation. Beyond this the virulency of the 

 poison cannot be increased and this constitutes the virus fixe (fixed or 

 unchanged virus) of Pasteur. 



The spinal cord of the rabbit dead of virus fi,xe is dried in a glass cylinder 

 with potassium hydrate. The cylinder is placed in a cool dry place and 

 each day small bits of the cord are cut off and placed in a vial of glycerin. 

 At the end of fourteen days the virus is no longer capable of producing 

 hydrophobia in rabbits, but the animal inoculated with it can withstand 

 the thirteen days virus (which was preserved in the glycerin) and so on 

 down the scale, until finally the rabbit can withstand the virus fixe-mthoxit 

 experiencing serious effects. 



In man it is customary to begin the treatment for rabies (or suspected 

 rabies) with the nine day cord (hypodermic injections of the cord emul- 

 sions) and to give each succeeding day a virus one day stronger, until 

 finally the virus fixe is injected without producing untoward symptoms. 

 The individual thus treated is now able to withstand the much weaker 

 virus from a dog or other animal suffering from rabies. As the result of 

 this mode of treatment the mortaUty rate from rabies is now less than i 

 per cent. (Ravenel). Those bitten by dogs (or wolves, skunks, cats) 

 suffering from rabies or suspected of suffering from rabies, should cleanse, 

 cauterize and disinfect the wound at once, and then immediately proceed 

 to a Pasteur Institute and submit themselves for treatment. The ear- 

 lier, after infection, the treatment is begun the more likely will the results 

 be satisfactory. The vaccine is, however, now so prepared as to make 

 home treatment possible. The graded doses of the virus put up in 

 sterilized ampules are ready for immediate use by the family physician. 



