GENERAL PROPERTIES AND ACTIONS OF THE VENOM. 63 



sound. In rabbits and guinea-pigs there occurs occasionally a conspicuous 

 flow of tears, and guinea-pigs develop an extreme rigidity of the abdominal 

 walls. In order to see whether this symptom might be due to the operation, 

 we injected control guinea-pigs with salt solution and found that the abdominal 

 walls remained relaxed. 



The heart continues to beat after the respiration has ceased, sometimes 

 for a considerable time 10 to 30 minutes in the warm-blooded animals and 

 many hours in frogs. The auricles beat after the ventricle has stopped. Occa- 

 sionally the cardiac rhythm is disturbed, the auricles beating oftener than the 

 ventricle. As a rule the heart stops in diastole, but may at times stop in systole. 



Santesson records a curare-like effect of the poison, which was not mani- 

 fested in our experiments. We found that in frogs which had died several 

 hours previously as a result of the injection of venom, mechanical stimulation 

 of the sciatic nerve would cause twitching of the leg muscles, and the same 

 effect was observed in mice immediately after death. 



Mitchell and Reichert believed the venom to be a heart poison. In the 

 few experiments that they made they used very large doses and brought about 

 death very suddenly. Probably by this means they caused a reflex stopping 

 of the heart, but that death is not due to a direct effect upon the heart we saw 

 in very many cases where mammalian hearts continued to beat for 30 minutes 

 and frogs' hearts for several hours after death. 



Denburgh and Wight (Am. Journ. Phys., 1900, 4, p. 209) had previously 

 reached a conclusion identical with ours; they also had decided that the imme- 

 diate cause of death was in respiratory failure. The observations of Denburgh 

 and Wight upon the physiological effects of heloderrna venom are in substan- 

 tial agreement with our own. \Ve have injected more than 360 warm-blooded 

 animals with heloderma venom, and although these have not all received con- 

 tinuous detailed inspection, nevertheless many have been kept under close 

 observation. From the history of these, we have selected the following typical 

 records : 



Rabbit 2, 500 g. 



MAY 30, 9 h 20 m injected intraperitoneally 0.15 c.c. sterile venom in 1 c.c. NaCl 0.85 

 per cent. 9 h 55 m signs of paralysis, unable to walk. 10 h 10 m drowsy. 

 10 h 15 m unable to hold up head; breathing rapid. 10 h 20 m appears to be dying; 

 reflexes absent. 10 h 25 m breathing labored, slower. 10 h #7 m dying; heart- 

 beat slow and weak. 10^35 m occasional gasps; heart-beat not felt. 10 h 40 m 

 stopped breathing, heart still beating, very weak. 

 Rabbit 4, 1000 g. 



MAY 30, l h 34 m injected 0.1 c.c. venom into ear-vein. Jf h 3o m pupils contracted. 

 1 h 86 lying down ; heart-beat weak ; breathing rapid . 1 h 37 m heart-beat weak, 

 fast; reflexes present, pupils contracted. I h 38 m heart-beat weak, slow; breath- 

 ing rapid, strained. l h 39 m pupils excessively contracted; ears bloodless. 

 l h 40 m convulsions; pupils dilate, reflexes present. l h 4-5 m occasional respi- 

 ratory gasps. l h 46 m reflexes still present; convulsions. l h 49 m reflexes 

 absent; heart action slow. l h 50 m dead; chest opened; heart still beating; 

 blood not clotted in heart; clots quicklv after escape into chest cavity. 

 Guinea-pig 41, 600 g. 



MAY 31, 12 h 00 m injected subcutaneously 0.1 c.c. venom in 1 c.c. NaCl 0.85 per cent. 

 12* 30 m lies down. 12 h 40^ breathing rapid. l h 30 m falls on side. 2 h OO m 

 breathing very strained, right legs paralyzed. # h 30 m breathing difficult, 

 slower. 2 h 4$ m lying on side; tetanic convulsions when stimulated. 2 h 50 m 

 dying. 3 h 10 m dead. 



