192 



Scientific Proceedings (114). 



dietary factors just mentioned can be made a limiting factor in 

 the rate of regeneration, if the hemorrhage is sufficiently severe. 

 Experiments are now in progress to determine the role of iron in 

 blood regeneration. 



96 (1678) 



Studies on the lytic agent of Bordet and Ciuca. 



By ANDRE GRATIA. 



[From the Laboratories of the Rockefeller Institute for Medical Re- 

 search, New York.] 



We owe to the kindness of Doctor Bordet a strain of B. coli 

 with which he carried on his studies, a certain quantity of the 

 corresponding lytic agent and a typical mucoid strain of his 

 modified coli. With this material we have observed the following 

 facts. 



1. The inhibition produced by the lytic principle on the 

 growth of B. coli is greatly influenced by the reaction of the 

 medium: faint in a slightly acid (P H 6.8) or neutral (P H 7.0) or 

 even slightly alkaline broth (P H 7.4), it is much stronger in a more 

 alkaline medium (P H 8.0 or 8.5). 



2. We have isolated from the original strain of B. coli two 

 types of organisms: the one, Type S, 1 is sensitive to the lytic 

 agent; the other, Type R, 1 is much more resistant. These types 

 are distinguished also by other characteristics: type S grows 

 quickly in artificial medium and is non-motile; type R grows 

 more slowly, is extremely motile, much less phagocytable and 

 more virulent. Both types ferment carbohydrates, saccharose 

 excepted; type R decolorizes neutral red, type S does not. Both 

 types keep their individuality even after passage through a 

 guinea pig. 



3. The original lytic agent was found to be specific; it acted 

 exclusively on the coli with which the guinea pigs had been in- 

 jected. By allowing this original lytic principle to act on broth 

 cultures of our two types of B. coli, we have obtained two new 

 filtrates. The first, resulting from dissolution of the sensitive 



1 S = sensitive; R ■ resistant. 



