10 THE VENOM OF HELODERMA. 



An interesting consideration suggested by various investigators is that 

 adsorption of the liemolj'zing substance represents the first step leading to 

 hemolysis. We furthermore know that blood-serum inhibits venom hemoly- 

 sis. Does serum exert this inhibiting action by preventing adsorption of the 

 hemolyzing agency by the corpuscles? From our results it is clear that the 

 chemical character of the adsorbent is not the determining factor in adsorption. 

 Carmine, kaolin, aluminium oxide, and especially charcoal are adsorbent 

 substances. The electric charge of the adsorbing material, therefore, does, 

 at least in this case, not seem to be the principal factor that determines 

 the strength of adsorption. 



The marked tendency of the venom of Heloderma to be adsorbed became 

 apparent very early in our studies. After boiling cobra venom and thus pre- 

 cipitating its albuminous material, its toxic principle, which the poison of 

 heloderma venom resembles so closely in its action, is found in the liquid part, 

 while the venom of Heloderma is partly adsorbed by the coagulum produced 

 during the process of boiling, and its tendency to be so readily adsorbed by 

 many substances interfered markedly with its chemical analysis. Doctor 

 Alsberg found that the majority of the methods used so successfully by Faust 

 in his analysis of cobra and crotalus venom were not applicable in the case of 

 heloderma venom, on accoimt of the readiness with which it is carried down 

 with various precipitates; but by a modification of one of the methods used by 

 Faust for isolating the crotalus toxin, he succeeded in obtaining the heloderma 

 venom in a state in which it no longer gave the biuret reaction, thus proving 

 that its poisonous principle is also a substance free from proteid or only sec- 

 ondarily combined with it. It shows also in this respect its close relation to 

 snake venoms. 



A more extended chemical analysis of the venom of Heloderma was impos- 

 sible on account of the great difficulty we incurred in obtaining quantities of 

 venom sufficient for this purpose. The same difficulty prevented us from 

 carrying out studies in immunity as far as we had planned to do. In order to 

 produce an antivenin against heloderma venom through injection of venom 

 into animals, relatively enormous quantities of the venom would have to be 

 used — very much more than was at our disposal. We had therefore to con- 

 tent ourselves with demonstrating the ])ossibility of active immunization of 

 rabbits against the venom of Heloderma. 



Precipitins are much more readily found than antitoxin in the serum of 

 rabbits repeatedly injected Avith venom. If we consider the chemical char- 

 acter of the venom as established by Alsberg, and furthermore the fact that 

 this precipitin produced in rabbits reacts not only with the venom but also 

 with the blood of Heloderma, although less markedly, there can be little doubt 

 that the precipitin was produced in response to the injection of certain proteid 

 material admixed with the poison of Heloderma proper, and not of the venom 

 alone. Inasmuch as this precipitin reaction is quantitatively stronger with 

 venom than with the blood of Heloderma, we may conclude that the proteids 

 of the venom gland and of the blood are not identical — a further confirmation 

 of the chemical specificity of the different organs of the same individual. 



