392 Hydrophobia, Lyssa, or Rabies 



furnishes enough material to immunize 20-25 patients, the initial 

 cost is neghgible. The worli can be undertaken in any hospital or 

 municipal laboratory without increasing the staff or the expense. 

 To be able to prepare at one time enough material for from six to 

 twelve months' use and to have this always ready for any number of 

 patients is such a lessening of labor and anxiety as only those who 

 have followed the classic method of drying cords can appreciate. 



If the conclusion of Harvey and McKendrick* be correct, and 

 " the immunizing power of any given portion of a rabies cord is a 

 function of the unkilled remnant of the rabies virus which is con- 

 tained in that cord," one should be able to find out Avith mathe- 

 matical certainty how many minimum infective doses will produce 

 a definite degree of immunity. For this purpose they suggest that 

 the virulence of the virus is expressed in "units," one unit being 

 the smallest amount which, when injected intracerebrally into a 

 full-grown rabbit, will produce paresis on the seventh day. 



Specific Treatment. — Babes and Leppf thought that the serum 

 of animals that had received repeated injections of the crushed 

 nervous tissue of rabid animals was neutralizing or destructive to 

 the rabies virus in vitro, called it "antirabic serum," and believed 

 that it conferred a defensive power upon other animals. Marie,! 

 however, found it to be a simple neurotoxic serum and inert in its 

 action upon the virus. It is never used in the treatment of rabies, 

 at present. 



* "Theory and Practice of Anti-rabic Immunization," Calcutta, 1907. 



t "Ann. de I'Inst. Pasteur," 1889, III. 



t " Compt.-rendu Soc. Biol.," June 18, 1904, LVi, p. 1030. 



