DISEASES OF THE NERVOUS SYSTEM. 239 



usual. True, in some rare instances in the human subject, 

 pain has been experienced in the region of the wound for a 

 considerable time after the receipt of the injury, and still more 

 rarely a quickened pulse and slight fever have been present 

 from this time until the disease became manifest. In other 

 exceptional cases silent changes seemed to be taking place in 

 the constitution, evidenced by general debility, a quick, weak, 

 and easily excited pulse, sallow looks, and sunken eyes. But, 

 as a rule, the health remains to all appearance the same as 

 before the inoculation ; and so subtle is the posion that, ac- 

 cording to Van Swieten, persons who afterwards die of hy- 

 drophobia may, in the .ncubatory stage, contract diseases, of 

 various kinds, even virulent diseases such as variola, without 

 the course of the rabies being thereby modified in the least, 

 or its evolution retarded. 



" What occult influence is at work, what changes may be 

 taking place previous to the manifestation of the first symp- 

 toms, is a matter of pure hypothesis. The venom of the 

 cobra, hydrocyanic acid, strychnine, and other poisons, pro- 

 duce effects more or less prompt and decided, according to 

 the amount introduced into the body of any animal, and we 

 can exactly prognosticate not only the result, but the time 

 about which it should occur. The virus of contagious dis- 

 eases, and more particularly hydrophobia, differs from these, 

 inasmuch as a minute quantity is as potent in inducing its 

 particular malady, in a certain time, as a large quantity ; and 

 in the special disease now under consideration it may lie in a 

 latent condition for a long period without affording the slight- 

 est indication of its presence." * 



Duration. — The duration of rabies is rarely long — from 

 one to ten days may be taken as the two extremes. A few 

 cases have been noted over the latter period ; but they are 

 very exceptional instances, and attended with some degree 

 of doubt. Those in my own experience have been from four 

 to five days; most of them haye died on the fifth. 



* Fleming's "Rabies and Hydrophobia," pp. 165, i66. 



