IMMUNITY AGAINST MICROBES. 429 



Further, MetschnikofF proved that the bacilli of the first 

 vaccin of swine fever live a long time in the anterior chamber 

 of the eye of rabbits, as well as in the eye of dogs, which are 

 naturally immune against swine fever. 



One rabbit, after having been rendered immune by seven 

 injections of the virus, was finally inoculated into the anterior 

 chamber of the eye with the first vaccin. In spite of the previous 

 inoculations, a large number of leucocytes emigrated into the 

 anterior chamber. A drop of aqueous humour examined twenty- 

 two hours after the operation gave a pure culture of the first 

 vaccin, whilst another drop, taken after forty-eight hours, 

 contained no bacilli. The bacilli of the first vaccin were 

 generally contained in the interior of leucocytes which had 

 found their way into the anterior chamber. 



A small case composed of four cover-glasses joined together 

 with sealing-wax, and filled with the virus of swine fever, was 

 introduced under the skin of a rabbit. One hour after its 

 introduction the case was already full of leucocytes contain- 

 ing bacilli, which stained quite as well as those lying in the 

 exudation fluid ; on cover-glasses withdrawn two and a half 

 hours after their introduction under the skin of a rabbit, which 

 had resisted six former injections of the virus, the number of 

 leucocytes containing bacilli in their interior was consider- 

 able. In all M. Metschnikofl''s experiments with cover- 

 glasses the bacilli were very quickly taken into the interior 

 of wandering cells, which gradually became more and more 

 numerous at the point of inoculation. 



A glass-case was filled with the virus of swine fever and left 

 for fifty-one hours under the skin of an immune rabbit. It was 

 then found that almost all the bacilli were contained in the 

 interior of cells and showed marked signs of degeneration ; 

 their outlines had lost their customary clearness, stained 

 badly, and their contents had become granular. On the other 

 hand, it was found that in glass-cases placed under the skin 

 of non-immune rabbits the greater number of the bacilli, 

 although surrounded by phagocytes, appeared perfectly normal 

 and stained well. 



