248 The Management 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 cther 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. 1n 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 
poison that, according to Van Swieten, persons who after- 
wards die of hydrophobia may,inthe 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. 
