THE VENOM OF HELODERMA. 



INTRODUCTION. 



While considerations of a practical as well as of a theoretical nature led 

 to the study of snake venoms, the interest in the venom of Hcloderma is more 

 purely scientific and of comparatively slight practical importance. No deat h 

 of a human being has come to our knowledge that can be attributed to the bite 

 of a Gila monster. A bite from this animal is in man either followed bj^ no 

 symptoms at all or by a local swelling, perhaps extending to the shoulder, if 

 the bite affected the upper extremity. The swelling disappears within a short 

 time, but it may be followed by a long-continued weakness of the hand, with 

 sensations of discomfort lasting over several years. The preparation of an 

 antivenin so desirable in the case of snake bites is therefore of little importance 

 in the case of Heloderma. From a theoretical point of view, on the other hand, 

 a study of the venom of Heloderma is of considerable interest. We have 

 learned much of the mode of action and of the constitution of snake venoms 

 through the extensive studies of S. Weir Mitchell and Reichert, Calmette, 

 Lamb, Flexner and Noguchi, Keyes, Fraser, von Dungern and Coca, Bang, 

 and especially Faust, with many others. 



Relatively little of a definite character is known concerning the venom^of 

 Heloderma. The investigations of Santesson and van Denburgh and Wight, 

 which followed the observations of S. Weir Mitchell and Reichert, were neces- 

 sarily limited in their scope, mainly in consequence of the small amount of 

 venom at their disposal. Data which permit a comparison between the mode 

 of action and constitution of snake venoms and the venom of the only other 

 poisonous reptile known, the Heloderma, are of great theoretical interest. An 

 intimate understanding of the different steps by means of which the venom 

 gains entrance into certain cells and exerts its destructive action on the con- 

 stituents of these cells is of fundamental pathological importance. The number 

 of unknown factors coming into play during these processes is, however, very 

 great, and the number of equations with which we can operate must be pro- 

 portionately increased. We undertook, therefore, to supply the data which 

 will render more accessible the venom of Heloderma for future detailed study of 

 certain problems. Not rarely our ovm investigations had to cease when the 

 point was reached where more far-reaching studies promised to yield results 

 of importance, and the further cultivation of this field had to be left to future 

 investigations. Under these circumstances it may not be without interest to 

 point out some of the results of our investigations, and especially those findings 

 which may serve as a starting-point for future research. 



The poison glands of Heloderma and of snakes differ somewhat in position 

 and structure. The poison gland of snakes is considered to be homologous 

 to the parotid of mammals, while in Heloderma it corresponds to a sublabial 



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