196 ON ANIMAL AND 



eases, in most instances, is the introduction of 

 the saliva of a rabid animal, most frequently the 

 dog, into a wound inflicted by its bite ; which, 

 being absorbed and conveyed into the blood 

 vessels, produces the train of symptoms we have 

 described. It has occasionally happened how- 

 ever, that a similar disease to hydrophobia has 

 occurred in the human subject, where no bite 

 could be traced to any animal whatever. In 

 that case, it has been denominated spontaneous 

 hydrophobia ; and when we add to these facts 

 the circumstance, of only one, out of about thirty, 

 being seized with the disease who have been 

 bitten by dogs supposed to be rabid; it exemplifies 

 in a striking degree our ignorance of its causes, 

 and what a wide field is still open for discovery 

 upon a subject, in which the interests of humanity 

 are so deeply concerned. Again, we are as 

 unacquainted with the cause of the dog species 

 being so peculiarly liable to this disease, as we are 

 with the manner in which it produces its effects, 

 on the human constitution ; or whether, in the dog, 

 it is spontaneously produced, or is communicated 

 by contagion only, or whether it depends upon 

 particular habits, modes of diet, or certain pri- 

 vations, or upon an especial constitution of the 

 atmosphere. All that we know is, that it appears 

 more frequently in some seasons than in others ; 

 that it is not confined to hot or cold weather, 

 though the extremes of temperature are more 



