ILEMOLYSINS OCCURRING IN TISSUE FLUIDS 459 



to it some inactivated goat's serum (that is, containing only 

 amboceptors). 



B. A hsemolytic normal serum is, as we have seen above, 

 inactivated by heating it to 55 C., so that it can no longer lake 

 the erythrocytes which it normally could. If this inactivated 

 serum be mixed with some serum of a third animal, which, in 

 itself does not haemolyse the erythrocytes under examination, the 

 complement of this non- haemolytic serum may activate the inert 

 serum and so produce haemolysis. This result depends on the 

 fact that every serum contains various complements ; if, then, a 

 group of sera, in themselves non-haemolytic towards the erythrocyte 

 used, be tried systematically, one will be got in which one or more 

 of the complements which it contains will fit the haptophoric 

 group of the amboceptor, and so complete the reaction. 



II. ELEMOLYSINS OCCURRING IN THE TISSUE FLUIDS OF ANI- 

 MALS LOWER THAN THAT FROM WHICH THE ERYTHROCYTES 

 ARE DERIVED 



The most interesting of those is snake venom. This is really a 

 toxin, and its injection in gradually increasing dosage causes anti- 

 venoms to be produced in the inoculated animal; just as toxins 

 produce antitoxins when similarly injected. Snake venom is 

 a complex fluid containing not one, but several cytolytic bodies 

 (i.e. bodies capable of dissolving cells) ; one of these acts on 

 erythrocytes, producing haemolysis. This haemolytic action can 

 be prevented by mixing the venom with anti-venomous serum, 

 and such a mixture, when inoculated into a susceptible animal, 

 no longer kills it. The venom, therefore, becomes neutralised at 

 the same time as the haemolysin (Stephens and Myers). The 

 haemolytic action of snake venom differs somewhat in its nature 

 from that of other haemolytic bodies. This fact was shown by 

 Flexner and Moguchi( 5 ), who found snake venom to contain 

 amboceptors alone ; for when they mixed it with erythrocytes of 

 the ox and goat, which had been very thoroughly washed free of 

 all possible traces of adherent serum, no haemolysis, but only 

 an agglutination of the erythrocytes resulted. If a little normal 

 serum were now added to this mixture of washed erythrocytes 

 and snake venom, haemolysis at once followed. The amboceptors 

 of snake venom are very stable bodies, for they can stand 

 heating to 90 C. 



