138 PASTEUR AND HYDROPHOBIA m 



ence that he has been so infected is based on the 

 knowledge of the condition of the dog that bit the 

 patient, and on the extent of the injury inflicted ; but 

 the knowledge of the actual state of the dog which 

 inflicted the bite upon a person Avho, therefore, has 

 reason to fear an attack of hydrophobia is often want- 

 ing. It is often merely " feared " or " supposed " that 

 the dog was rabid, and has not been actually proved 

 that such was the case. In many cases the only proof 

 that the dog really was rabid would be found in the 

 development of hydrophobia in the man bitten by the 

 dog, the dog itself having been destroyed. This, too, 

 would be the only definite proof possible that the 

 patient had received a sufficiently profound wound to 

 carry the poison into the system, or, again, that the 

 patient is not naturally " immune " or " refractory " to 

 the poison. Accordingly, it has been necessary for 

 M. Pasteur to test his treatment upon a very large 

 number of cases, so as to obtain a statistical result 

 which may be compared with the general statistics of 

 the eff*ects following the bite of reputed rabid dogs. 

 Also, it is possible out of a large number of cases for 

 M. Pasteur to select, without any other determining 

 motive, those cases in which the dog which inflicted 

 the bite was actually proved to be sufl*ering from 

 rabies, either by the result of its bite on other indi- 

 viduals, or by experiments made by inoculating other 

 animals from it after its death. Such a selection of 

 his cases has, it is stated, already been made by M. 

 Pasteur. We have yet to await from M. Pasteur's 

 own hand a critical account of the results obtained in 



