ILEMOLYSINS IN BACTERIAL CULTURES 461 



on to tissue cells does not imply that it should poison these, but 

 it nevertheless occasions an overproduction of biogen receptors 

 so that anti -bodies are produced. 



III. H^EMOLYSINS IN BACTERIAL CULTURES 



Both bacteria and bacterial toxins can produce haemolysis. 

 Koch first noticed this for cholera vibrios, and some years later 

 van de Velde ( 5 ) showed that a filtered culture of staphylococcus 

 did the same thing. This so-called staphylolysin acts most 

 sensitively on rabbit's erythrocytes. Many normal sera (that of 

 a man) when added to the staphylolysin diminish its hsemolytic 

 power; in other words, these sera contain anti-bodies for 

 staphylolysin. Now, according to Ehrlich's theory, these latter 

 must be free receptors which fit on to the haptophoric group of 

 the hsemolysin amboceptor, and thereby prevent its uniting with 

 the erythrocytes. They must have been cast off from tissue cells, 

 where, when attached, they functionated in assimilating food. It 

 is merely an accident that they should fit the haptophoric group 

 of the staphylolysin amboceptors. 



Hsemolysins have been also discovered in cultures of the tetanus 

 bacillus. In these cultures, the tetano-lysin exists alongside of a 

 tetano-spasmin, which latter is the specific toxin, producing tetanus. 

 That these two toxins (tetano-lysin and tetano-spasmin) are 

 distinct from one another is proved by the fact that erythrocytes 

 take up the tetano-lysin but not the tetano-spasmin, and also by 

 the fact that tetano-lysin is more easily destroyed by heat than is 

 tetano-spasmin. Horse's and rabbit's erythrocytes are especially 

 sensitive towards tetano-lysin, and specific anti-bodies against 

 tetano-lysin become developed in animals inoculated with tetanus. 



Many other cultures have been shown to contain hsemolysins, 

 and no definite relation can be shown to exist between the viru- 

 lence of a bacterium and the hsemolytic power of the medium in 

 which it is grown ; indeed, the strongest bacterial hsemolysin 

 hitherto observed (by Todd) was found in a saprophyte (B. 

 Megatherium). A hsemolysin contained in pyocyaneus cultures 

 has been shown by Bulloch and Hunter ( 10 ) to be distinct from 

 the pyocyaneus toxin which such cultures also contain : another 

 proof of the complexity of toxins. 



Bacterio-hsemolysins can also produce their action in the blood- 

 vessels, and this may account for the ansemic symptoms so common 



