138 CLINICAL BACTERIOLOGY AND 



vaccine was injected, development of the disease would be 

 prevented, and that immunity would be maintained for one 

 year at least. 



In the year 1885 Pasteur, going forward with the know- 

 ledge he already possessed as the result of his experiments 

 upon animals, successfully vaccinated a boy who had been 

 bitten by a rabid dog. 



Since then this mode of prophylactic treatment and its 

 modifications has been carried out on an extensive scale, 

 with excellent results. Hogyes prepared a vaccine by 

 triturating normal saline solution with virulent spinal cords 

 of rabbits, making emulsions of different strengths — i.e. : 



1 in 200. 



1 in 5,000. 

 1 in 2,000. 

 1 in 500. 



1 in 100. 

 1 in 10. 



These he injected every two hours, beginning with the 

 most attenuated dose. He found that a dog so treated 

 would resist infection if bitten by a rabid dog or injected 

 artificially with the virus. 



These experiments also demonstrated an interesting fact 

 that it is not the attenuation of the virus, as in Pasteur's 

 vaccine, but a reduction of the amount which is important. 



Tetanus. 



Tetanus is a specific infective disease due to the action 

 of the bacillus of tetanus and its toxins. The bacilli are 

 found most commonly in garden soil, horse manure, and 

 road earth, and there must be an injury to the skin or 

 mucous membrane before an animal can become affected. 



The intestines of the horse have been found to harbour 

 the bacilli without producing a pathogenic condition. 



The bacilli located in a wound multiply, but seldom leave 

 the focus of infection ; they are, therefore, rarely found in 

 the blood-stream or vital organs. During the process of 

 their multiplication they manufacture a specific toxin, which 

 is taken up by the circulation and diffused over the entire 



