MABIES. 239 



cent. At Alfort they found the proportion to be about 33 per 

 cent., and at Lyons 26 per cent. In man 50 per cent, of the bitten 

 subjects develop the disease; but if we sum together the cases of 

 true rabid and " suspected " dogs, the proportion is reduced to 

 about 8 per cent. Hoges gives 15 per cent. 



It has not up to the present time been definitely determined 

 that the disease can be transmitted through the medium of milk 

 and meat, or by any other intermediate agents. The period of 

 incubation between the time of the actual bite and the appearance 

 of the disease is not as yet definitely fixed. This peculiar fact 

 may be explained in different ways. Some have contended that 

 a form of encysting of the poison in the inoculated region takes 

 place. 



Another explanation of the various lengths of the period of 

 inoculation is the theory that a small amount of poison enters the 

 body, and that this has to be reproduced according to the quantity 

 inoculated until there is sufficient virus in the body to develop the 

 disease. Pasteur has positively demonstrated that the period of 

 inoculation is much longer when the amount inoculated is in very 

 small quantities, and also in cases where the poison is very much 

 weakened. The disease may not be developed at all. This theory, 

 hoVever, does not thoroughly explain the varying length of the 

 period of incubation, and some observer may yet be able to give 

 ns a more thorough and reliable explanation. 



The character of the rabic poison is as yet unknown. We have 

 to accept the theory that it is a micro-organism, for Paul Bert was 

 able to render the infectious material innocuous by filtering it 

 through tablets of gypsum. Hallier claims to have found a micro- 

 coccus in the blood of rabid dogs and horses. Zurn, Frank, and 

 Bollinger obtained negative results. Pasteur has found fine gran- 

 ulations in the brains of rabid animals, which could be colored with 

 aniline, and he is inclined to consider this as a specific organism 

 of rabies, but he was not able to make any cultures from them. 

 Chamberland and Roux noticed micro-organisms in the blood of 

 rabid animals, which were shaped like fine network. Rabbits 

 which had been inoculated with such cultures became very sick, 

 but did not show any symptoms of rabies. Babes noticed in the 

 brain and spinal cord of rabid subjects microbes which were crowded 

 together, forming shiny granulations. These were colonies of 



