242 DISEASES OF TRUE INFECTION. 



mission over forty to fifty generations, Pasteur has obtained a 

 fixed virus wliich has a constant and regular virulence. This he 

 obtained from the rabbit's spine, and is even more " intense than 

 the rabic poisoning of a furious dog, and he was able to produce 

 the disease from eight to ten days after inoculation. 



8. If the brain and spinal cord are cut into small portions and 

 mixed with fixed virus, and subjected to a careful and slow drying 

 process under 20° Celsius, the infectious substance gradually loses 

 its activity and becomes perfectly harmless at the end of fourteen 

 days. We may thus obtain an inoculating substance which possesses 

 varying degrees of intensity, and it is possible to inoculate ani- 

 mals with weakened virus, rendering them proof against direct 

 inoculation from a rabid dog. This inoculation is made by means 

 of a hypodermatic syringe directly under the abdominal muscles. 

 After twelve or thirteen mild inoculations, each inoculation being 

 increased in intensity, the subjects become proof against the inoc- 

 ulation of the disease in any form whatever. When Pasteur first 

 made these inoculations, using the material in varying degrees of 

 strength, and at periods which took at least ten days, he was able 

 later on to make all the inoculations within twenty-fours hours, 

 making each inoculation two hours apart. 



These observations have been proved correct by scientists in dif- 

 ferent parts of the world. Pasteur concludes from his observations 

 that man may be protected against rabies by inoculation, and this 

 is even possible when infection has already taken place. As is well 

 known, Pasteur, before his death, applied this theory for some years 

 upon inoculated people, and he stated that he reduced the mor- 

 tality, which varied from 16 to 60 per cent., down to 1/2 to 1 per 

 cent. Similar results have been obtained in other institutions 

 established in different parts of the world by following the same 

 methods ordinarily practised by Pasteur. Of 454 cases of patients 

 inoculated by rabid animals, which were afterward treated with 

 weakened virus, only 1 to II/2 per cent, of which died. 



Pasteur's system has been opposed by several authors. Frisch 

 claims that it is impossible to prevent the development of rabies 

 after infection by means of Pasteur's preventive inoculation, as the 

 poison has reached the cranium, and it is too late to do anything. 

 This opinion is indorsed by Amoroso and de Eenzi; and Babes, 

 after numerous experiments, arrived at the conclusion that it is 



