242 THE VENOM OF HELODERMA. 



Indeed, Noguchi showed that pancreas lipase when freed from fat loses its 

 hemolytic power, while the venoms of various snakes are activated by lecithin, 

 triolein, and oleinic acid. Since the venom of Heloderma is hemolytic the occur- 

 rence of lipase becomes interesting, especially since it has been shown that the 

 venom contains appreciable quantities of alcohol and ether-soluble material. 

 It seemed, therefore, worth while to study the lipolytic action of the venom in 

 detail. Two points seemed important. In the experiments reported above, 

 relatively large amounts of venom were used. It was therefore necessary to 

 determine whether positive results could be obtained with smaller amounts. 

 Furthermore, the thermolability of the venom seemed to demand further inves- 

 tigation, since this point has not been much investigated by previous authors. 

 At the same time the effect of the reaction of the medium, the action on oil 

 instead of lecithin, the effect of manganese, and of bile salts were also considered. 

 The following series of experiments was set up and all except some of the 

 controls (Nos. 1, 2, 6) incubated for 60 hours. Then 25 c.c. of alcohol and a 

 little phenolphthalein were added to each and the acidity titrated. The con- 

 trols, Nos. 1 and 2, were titrated at once. From the value obtained the acidity 

 of the control is subtracted and the result represents the acid formed in the 

 given experiment. 



No. 1. 1 c.c. 1 per cent venom solution, 10 c.c. 2 per cent lecithin emulsion, 1 

 c.c. water, 3 drops toluol. This served as the control and was titrated 

 immediately. Cubic centimeters N/10 alkali required for neutrali- 

 zation, 1.5. 



No. 2. The same as No. 1. Number of cubic centimeters of N/10 alkali 

 required for neutralization, 1.8. 



No. 3. The same as No. 1. The titration, however, was done after 60 hours 

 of incubation at 38 C. and required 4.9 c.c. N/10 potassium hydroxid. 

 Subtracting the average of the controls (Nos. 1 and 2) this leaves 

 3.25 c.c. 



No. 4. 1 c.c. 1 per cent venom solution was heated to 60 C. for 30minutes. It 

 was cooled; and 10 c.c. 2 per cent lecithin emulsion, 1 c.c. water, and 

 3 drops of toluol added. The increase in acidity after incubation 

 corresponded to 2.5 c.c. N/10 potassium hydroxid. Evidently the 

 lipase was not completely destroyed by the heating, but only weakened. 



No. 5. The same as No. 4. Acidity = 2.1 c.c. N/10 potassium hydroxid. 



No. 6. 1 c.c. 1 per cent venom solution was heated to 100 C. for 10 minutes. 

 In all other respects the conditions were as in Nos. 4 and 5. Acidity 

 = 1 c.c. N/10 potassium hydroxid. Evidently the heating had al- 

 most completely destroyed the activity. 



No. 7. 1 c.c. 1 per cent venom solution, 10 c.c. 2 per cent lecithin emulsion, 

 0.5 c.c. of 0.2 per cent sodium taurocholate solution, 0.5 c.c. water. 

 Increased acidity after usual incubation 2.7 c.c. N/10 potassium hy- 

 droxid. Evidently the bile salt had not increased the lipolysis. 



No. 8. 1 c.c. 1 per cent venom solution, 10 c.c. 2 per cent lecithin emulsion, 

 1 c.c. of an 0.8 per cent solution of manganese sulphate. Increased 

 acidity = 2.8 c.c. N/10 potassium hydroxid. Evidently the man- 

 ganese salts did not increase the lipolysis. 



No. 9. 2 c.c. water, 10 c.c. olive oil which had been rendered neutral by standing 

 in contact with powdered calcium carbonate for some time, 3 drops 

 toluol. Acidity after incubation =1.5 c.c. N/10 potassium hydroxid. 



