248 The Manage7nent and Diseases of the Dog. 



mentions an instance in which the incubatory period was 

 from seven to eight months, and another in which it was 

 fourteen months. He gives an average of three months.* 



With such variations in the incubative period, it is little 

 to be wondered at that persons, after being bitten, and 

 under what condition of the animal they know not, should 

 be filled with dread, and exhibit, especially those of nervous 

 temperament, great mental excitement. 



What takes place during this incubatory or latent period 

 we know not ; but it may be confidently asserted that in 

 no other malady is this interregnum more variable and 

 uncertain ; indeed, if we are to credit some reports, the 

 duration of the latent stage is indefinite. The capricious- 

 ness of the virus of rabies in this respect is certainly very 

 remarkable and unaccountable. The wounds produced by 

 rabid animals generally heal up readily, and leave but 

 slight trace, and to all appearances those who have been 

 injured appear to be as well as 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 se^ed 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 

 poison that, according to Van Swieten, persons who after- 

 wards die of hydrophobia may, in the incubatory 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 



* Fleming's "Rabies nad Hydrophobia," pp. 178—180. 



