152 BABIES. 



many of the most intelligent observers, recent as well as old. 



It is unnecessary to enumerate and describe all tbe influences which 

 have been cited as predisposing and accidental causes; in wearisome 

 arguments our best authorities have proved the theories untenable and 

 unfounded, and that all the causative conditions such as seasons of the 

 year, extremes of temperature, restraint, starvation, suppressed sexual 

 appetite, age, sex, and race are to be regarded neither as direct nor pre- 

 disposing causes. 



It is now universally accepted that the poison is communicated almost 

 invariably by means of the bite of a rabid or infected animal. 



Nothing is known of the specific infecting principle of rabies. The virus 

 is contained in the saliva and foam of the diseased animal, also in the 

 spinal cord, blood, and salivary glands; its existence in other portions of 

 the body is conjectured but not positively determined. Neither by chem- 

 ical or microscopic analysis of the saliva of rabid dogs hasthis virus been 

 detected. 



It increases by internal growth, and from other poisons it is distinguished 

 principally by this circumstance, that it remains within the vital organism 

 for weeks and even months without producing any diseased symptoms 

 whatever. 



In what manner, or by what course the specific poison penetrates the 

 body from the wound is unknown, neither has its action while within the 

 system been adequately explained. 



Two theories have been advanced; either the virus remains awhile con- 

 cealed and inactive at the seat of the wound or point of inoculation, and 

 only after a certain interval — at the expiration of the period of incuba- 

 tion — enters and circulates with the blood and other fluids of the body ; 

 or else the poison, by undergoing incessant reproduction, is constantly 

 supplied in fresh quantities to the blood. 



Virchow has compared the action of the poison to that of a ferment, 

 fresh particles of which are constantly being conveyed into the bJood 

 from the seat of the inoculation, producing through the medium of the 

 circulation the specific effect upon the nervous system. 



Experiments have proved that the bite of an infected— though appar- 

 ently healthy — dog, when inflicted during the period of incubation, or 

 slow development of the disease, has even then the power of communica- 

 ting it. Thamhayn collated nineteen cases, occurring in the human 

 subject, in which dogs, to all appearances healthy, but which subsequently 

 became rabid, produced by their bite hydrophobia, the result being fatal 

 in eighteen cases. 



The virus is probably capable of infection for some time after death but 

 hardly longer than twenty -four hours. That the same is inactive when 



