12 THE VENOM OF HELODERMA. 



The question how far the different effects of one and the same venom 

 depend on one toxic principle, or on the presence of multiple poisonous bodies, 

 is a problem much more difficult to decide. There can be little doubt that not 

 all actions of one venom are due to one single substance. We now know that 

 some of the ferments of the venom of Heloderma are not at all produced in the 

 venom-gland, but are evidently admixtures derived from elsewhere. Fur- 

 thermore, there can be little doubt that the substances present in some snake 

 venoms, causing or preventing the coagulation of the blood, are not identical 

 with the neurotoxins or with the hemolysins of the same venom. Still more 

 difficult to answer is the question how far other constituents of various venoms, 

 the neurotoxin, hemolysin, and other cytolysins, and hemorrhagin are identical. 

 The evidence we have concerning this point appears conflicting. On the one 

 hand, Faust's fundamental investigations into the chemical constitution of 

 venoms seemed to simplify these problems. According to Faust, ophiotoxin 

 exerts both a neurotoxic and hemolytic action, crotalotoxin in addition a hem- 

 orrhagic action comparable to arsenic, emetin, and sepsin. The preponder- 

 ance of the local effects in the case of crotalotoxin is said to be due to the greater 

 molecular weight of this venom as compared to ophiotoxin, which increases its 

 colloidal properties and causes it to be more slowly absorbed. On the other 

 hand, a good deal of evidence can apparently be adduced against this view. 

 We might especially mention the following facts: 



The heat-resistance of the so-called neurotoxin, hemolysin, and hemor- 

 rhagin is not identical in the same venom. This applies to the heloderma 

 venom, where the neurotoxin is distinctly more heat-resistant than the 

 hemolysin. Their resistance to the effect of certain chemicals varies. The 

 hemolytic principle can be extracted through some substances in which the 

 neurotoxin remains undissolved. The different constituents of a venom show a 

 different tendency to be adsorbed by certain materials. Various venoms differ 

 in the number and quantities of the various toxic constituents which they con- 

 tain. The antivenin produced through immunization with a certain venom 

 does not neutralize all the toxic constituents of another venom. Whether the 

 ophiotoxin and crotalotoxin of Faust are able to call forth the production of 

 antivenin, we do not yet know. 



It appears improbable that these substances could give rise to the produc- 

 tion of antibodies, graded in accordance with the relationship of the animals 

 from which the venoms were derived. There exists, therefore, a certain dis- 

 crepancy between the results of the purely chemical analysis of the venoms 

 and between the evidence obtained through the application of so-called 

 biochemical methods. In weighing the evidence we have to take into con- 

 sideration the fact that some of the conclusions based on the latter methods 

 are of such a remarkable character that we may find some difficulty in accept- 

 ing them. Thus studies of hemolysins and other cytolysins of snake venoms 

 by the method of selective adsorption lead to the conclusion that a single 

 venom contains an almost endless number of various cytolysins, and espe- 

 cially hemolysins. A venom would therefore constitute a mixture of poisons 



