176 PHY TO TOXINS AND ZOO TOXINS 



These are hemotoxins (hemolysins and hemagglutinins), leucocy- 

 tolysinsy neurotoxins, and endotheliotoxins (hemorrhagin). In 

 another place (see "Hemolysis") the nature of thehemolytic agent 

 is discussed, and the important observation of Flexner and 

 Noguchi, that the venom hemolysin is in the nature of an 

 amboceptor, 1 is described. Venom agglutinin is quite inde- 

 pendent of the hemolysin, for it is destroyed by heating to 75- 

 80, whereas the hemolysin is destroyed only partly at 100. 

 Agglutinin acts in the absence of serum complement, and there- 

 fore is not an amboceptor like the hemolysin ; it is apparently 

 more like the toxins in its nature. The agglutination of the 

 corpuscles does not interfere with their subsequent hemolysis. 



The leucocytotoxins are quite distinct from the hemolysins, 

 for after saturating . all the hemolytic amboceptors with red 

 corpuscles, the venom still shows its effects on the leucocytes, 

 which effects consist in cessation of motility and disintegration, 

 affecting particularly the granular cells. The leucocytotoxin, 

 however, resembles the hemolysin in that it appears to be 

 an amboceptor. Leucocytes are also agglutinated by venom, 

 possibly by the same agglutinin that acts on the red corpuscles. 



By saturating venom with either red corpuscles or nerve-cells 

 it is possible to prove that the toxic principle for each is distinct 

 and separate. Other sorts of cells, however, are able to com- 

 bine, or at least remove some parts of the toxic elements, but 

 to a much less degree. The neurotoxin, like the hemolysin, is 

 an amboceptor, and since venom contains no complement, the 

 neurotoxin has first to be supplied with complement by the 

 victim's blood before it can harm the cells. This is a remark- 

 able example of a substance, the complement, which is normally 

 intended for defense, acting as a toxic agent. 



The pronounced hemorrhage-producing property of serums, 

 particularly that of the rattlesnake, was also found to be due to 

 a specific toxin acting on the endothelium of the capillaries and 

 small veins, and not to the changes in the blood itself, as had 

 formerly been thought. This endotheliotoxin, which Flexner 

 and Noguchi call " hemorrhagin/' is quite distinct from the 

 other toxic substances, being destroyed at 75, a temperature 

 that leaves the neurotoxin and hemolysin uninjured. 



Variations in Venoms. In distribution among the vari- 

 ous poisonous reptiles these toxins are also quite distinct from 

 one another, which explains the difference in the effects of bites 



1 This use of the term hemolysin is usual, but not strictly correct, for the 

 amboceptor by itself is not hemolytic. A more exact statement would be that 

 the venom hemolysin is an amboceptor-complement complex (Ricketts). 



