INTERMITTENT FEVER. 317 



serve the virulence of the brain of a rabid animal for 

 three weeks. 



44 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. 



44 The same result is obtained by introducing the 

 virus directly into the blood. 



44 These methods of inoculation frequently give rise to 

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



44 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. 



44 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- 



