INTERMITTENT FEVER. 317 



serve the virulence of the brain of a rabid animal for 

 three weeks. 



" VI. In order to produce rabies with certainty and 

 rapidity, it is necessary to inoculate the surface of the 

 brain, in the cavity of the arachnoid, by means of 

 trephining. 



" The same result is obtained by introducing the 

 virus directly into the blood. 



" These methods of inoculation frequently give rise to 

 the disease at the end of six, eight, or ten days. 



" VII. Rabies communicated by introducing the virus 

 into the blood very often presents characters quite dif- 

 ferent from those of furious rabies, resulting from a bite 

 or from inoculation upon the surface of the brain, and 

 it is probable that many cases of silent rabies have 

 escaped observation. In the cases which may be denom- 

 inated medullary, prompt paralyses are frequent, furor 

 is often absent, and the rabid barkings are rare ; on the 

 contrary, the itching is sometimes terrible. 



" The details of our experiments lead us to believe 

 that, in the method by intravenous injection, the spinal 

 marrow is first attacked ; that is to say, that the virus 

 first fixes itself and multiplies in this locality." 



INTERMITTENT FEVER. The limits of the pres- 

 ent volume do not admit of an extended account 

 of the experimental evidence which has been ad- 

 vanced in favor of the parasitic-germ theory as 

 regards the etiology of the malarial fevers. The 

 fact that the malarial poison is evolved under cir- 

 cumstances which favor the development of low 

 organisms, and that its production has been pretty 

 definitely proved to be associated with the decom- 

 position of organic material of vegetable ori- 



