Haemolysins and B act erioly sins 19 



advantage in abandoning the term lysins, which certainly suggests 

 something more as to their effects. Corresponding terms are spermo- 

 toxin for toxin in serum which acts more especially on spermatozoa, 

 leucotoxin for serum which destroys leucocytes. Flexner and Noguchi 

 (II. 1902) separate the haemolysins into erythrolysins (dissolve red 

 corpuscles) and leukolysins (dissolve leucocytes). 



Besides the serum of animals the secretion of certain glands may 

 be cytotoxic, as is seen with snake venoms. Cytotoxins may also be 

 of vegetable origin, being either derived from bacteria or higher plants. 

 We shall refer to these elsewhere (see p. 28). The haemolysins act by 

 separating the haemoglobin from the stroma of the blood corpuscles, 

 causing the blood with which they come in contact to " lake." 

 Haemolysis may be effected also by hypotonic salt solutions, or by 

 destructive chemicals, but this apparently purely physical phenomenon 

 does not concern us. 



It is true that Baumgarten (16, xii. 1901 ; and 27, x. 1902) would explain 

 haemolysis as due to altered physical conditions brought about by haemolytic 

 sera, as seen in plasmolysis due to non-isotonic solutions. He however found that 

 this did not offer a full explanation, for a haemolytic serum acted more rapidly than 

 saline solution of equal specific gravity. He therefore supposes that the agglutinin 

 present in haemolytic serum causes this increased action, claiming moreover that 

 the agglutinin is identical with Ehrlich's immune-body. It appears to. him a priori 

 proViable that the serum of different animals may contain different quantities of 

 osmotic substance. He does not believe that the action of complement is similar 

 to that of digestive ferment, as considered by Buchner, Bordet, and EhrHch and his 

 school. 



Haemolysins may be present in certain normal sera, or they may 

 be artificially produced by injections of the blood of other animals than 

 that treated, if we except the observations upon isolysin.s. In their 

 fundamental characters the haemolysins, both natural and artificial, 

 correspond to the bacteriolysins ; they offer the advantage over bacterio- 

 lysins, that it is possible to experiment with them in the test-tube. 

 The discovery of the artificial haemolysins dates from Belfanti and 

 Carbone (1898). 



The Mode of Action of Haemolysins and Bacteriolysins. 



Bordet and Ehrlich have shown that there are at least two bodies concerned in 

 the liaemolytic or bacteriolytic action of a serum. The one is the specific immune- 

 body, which is thermostable ; the other is the thermolabile complement, which is 

 present in normal sera. The artificially produced haemol^'sins, namely those 



2—2 



