458 HSEMOLYSINS AND ALLIED BODIES 



the source from which they are derived. In this connection we 

 shall consider the following : 



I. Hsemolysins present in normal blood. 



II. Hsemolysins in the tissues of lower animals. 



III. Hsemolysins in bacterial cultures. 



IV. Hsemolysins in certain plants. 



I. H^MOLYSINS PRESENT IN NORMAL BLOOD 



In 1888 Mosso noticed that eel's blood was very poisonous 

 when injected into other animals. It was not till 1898 that the 

 cause of this was found to be a normally occurring hsemolysin in 

 eel's blood, very active towards the erythrocytes of most animals. 

 Similar hsemolysins have been discovered in the blood of various 

 other animals ; thus, to take another example, O5 c.c. of goat's 

 serum can lake 5 c.c. of a 5 per cent, suspension of rabbit's 

 erythrocytes. These natural hsemolysins appear to act in the 

 same way as do those experimentally produced, for, as 

 Daremberg ( 5 ) has recently shown, heating the serum to about 

 55 C. removes its hsemolytic power. These facts are of some 

 therapeutic interest, for they show us that intravenous injection of 

 foreign bloods may have a poisonous (i.e. hsemolytic) action ; but 

 that this can be removed by heating the serum to 55 C., a tempera- 

 ture which will not coagulate the proteids, but will destroy the 

 hsemolysin. A bactericidal action of normal serum has also 

 been described by Nuttall, Behring, and others. 



Further proof that normal hsemolysins act in the same way 

 as do those artificially produced is by no means easy to furnish, 

 since there is, in normal blood, only a trace of amboceptors with 

 a large excess of complement. That both amboceptor and com- 

 plement do form the hsemolysin in this case has, however, been 

 proved by the following experiments of Ehrlich and Morgenroth ( 9 ). 

 A. The serum of a normal goat can lake guinea-pig's erythrocytes ; 

 if, however, the serum and erythrocytes be kept at C., no 

 laking will occur, for, as explained on p. 447, there is, at this 

 temperature, no union between amboceptor and complement, 

 although amboceptor and erythrocyte do unite. If, after two 

 hours, the mixture be centrifugalised, the sediment will be found 

 combined with amboceptors and the supernatant fluid will no 

 longer hsemolyse guinea-pigs' erythrocytes (because it only 

 contains complements) ; it can be activated, however, by adding 



