4 THE VENOM OF HELODERMA. 



bridge studied by Hunter and Lamb. In contradistinction to these venoms, 

 the venom of Heloderma, although principally a neurotoxin, does not entirely 

 destroy the ganglia-cells. Its effect on the heart is very slight in vitro as well 

 as in vivo. Furthermore, it is of interest that the action of the venom on the 

 heart is reversible and that removing the venom can restore the heart action 

 (Githens). 



We also observe, in contradistinction to certain snake venoms with the 

 power to dissolve muscle-tissue, that the venom of Heloderma does not exert a 

 lytic effect upon the heart-muscle. The marked primary fall in blood-pressure 

 which takes place after injection of the venom must therefore be due to a 

 direct or indirect vasomotor action of the venom on the blood-vessels. In 

 this respect our results agree with those obtained by van Denburgh and 

 Wight. Fleisher, however, did not observe the strong antagonistic action of 

 adrenalin upon the venom noticed by the previous investigators. Further- 

 more, he could establish the fact that the diminution in the flow of urine during 

 a long-continued injection of venom dissolved in much 0.85 per cent NaCl 

 solution is not due to a direct injurious action upon the kidney on the part of 

 the venom, but corresponds to, and is merely the result of, the decrease in 

 blood-pressure. The interchange of fluid between the blood and body cavities 

 is not markedly influenced by the venom during an infusion with 0.85 per cent 

 NaCl solution. The elimination of fluid into the small intestines is, however, 

 increased under these conditions, and correspondingly we find that if death 

 follows an injection of venom, the small intestine contains much fluid; espe- 

 cially is this true of the guinea-pig. 



Two sequels of poisoning with the venom of Gila monster deserve special 

 mention, inasmuch as I have found no reference to them in the literature on 

 snake venoms, so far as the latter was accessible to me: (1) In the mouse we 

 find very frequently a rupture of blood-vessels near the optic nerve and pro- 

 trusion of the eyeball with subsequent opacity of the cornea or lens. (2) In 

 guinea-pigs we found ulcers and hemorrhages in the wall of the stomach. The 

 investigations of M. E. Rehfuss have shown that these ulcers are due to a 

 digestive action of the gastric juice; that the hemorrhages are usually second- 

 ary; that this effect is not specific for venom, but is found after the administra- 

 tion of a great variety of poisonous substances in cases in which the animal is 

 markedly affected by the toxic substance. Thrombi are present in the neigh- 

 borhood of the lesions, but are not the cause of the lesions. The factor that 

 makes the mucosa accessible to the digestive action of the gastric juice has yet 

 to be determined. Comparative studies in different species of animals (her- 

 bivorous and carnivorous animals) ought to yield results of interest. 



Other structural changes produced by the venom are slight and seem to 

 be especially noticeable after chronic poisoning. Even the slow action after 

 introduction into the peritoneal cavity of collodion capsules containing venom 

 caused no marked structural changes; they certainly formed a much less promi- 

 nent feature than the great loss of weight which we observed in such animals. 

 A study of metabolism under these conditions might be of interest and throw 

 light on the disturbances of metabolic equilibrium in states of chronic poisoning. 



