BIOCHEMICAL STUDIES. 241 



Lipase. 



Lipase was determined according to the method suggested by Michaelis.* 

 Some fresh lecithin was prepared from egg-yolk. The yolks were dissolved in 

 an equal volume of 10 per cent sodium choloride and the resulting solution 

 extracted with ether. The ethereal extract was concentrated by means of an 

 air current. The oily residue was extracted, till white, with acetone. The 

 undissolved residue was freed from acetone by exposure to air in a thin layer on 

 paper. Of this preparation a 2 per cent emulsion in water was made by shak- 

 ing. This emulsion was then used as the reagent. 



As lipase is exceedingly sensitive, and as its action is usually com- 

 paratively limited, it was decided not to use the venom solution, but to use 

 the finely powered venom in substance. The following tubes were therefore 

 made up : 



No. 1. 5 c.o. lecithin emulsion, 0.1 gm. powdered venom, 0.2 c.c. toluol. 

 No. 2. The same. 

 No. 3. The same. 



Tube No. 3 was examined at once. 5 c.c. of absolute alcohol were added 

 and the mixture filtered. The tube and the filter were then washed with two 

 successive portions of 5 c.c. of absolute alcohol. Tube No. 1 was treated in 

 the same fashion after 6 hours' incubation and No. 2 after 12 hours' incuba- 

 tion. The alcoholic filtrates were all titrated with N/10 potassium hydrate 

 and phenolphthalein as indicator. The following results were obtained: 



No. 1. 1.35 c.c. N/10 alkali required. 

 No. 2. 1.85 c.c. N/10 alkali required. 

 No. 3. (control). 0.70 c.c. N/10 alkali required. 



Subtracting the amount of acidity originally present in the control we obtain : 



No. 1. 0.65 c.c. N/10 acid formed. 

 No. 2. 1.15 c.c. N/10 acid formed. 



To make sure of these results a further control was made, bringing the solu- 

 tion to a boil before incubating. In this experiment 0.8 c.c. N/10 acid, very 

 little more than the control (No. 3), was required. It seems, therefore, reason- 

 ably certain that the venom contains some lipase. 



The occurrence of lipase in heloderma venom is a matter of considerable 

 interest. The occurrence of lipase in various venoms has been reported by 

 Neuberg and Reicher,f and Neuberg and Rosenberg, J and was by them and by 

 Noguchi brought into relation with hemolysis. Previously Delezenne^j and 

 Friedemann|| had discovered that neutralized pancreatic juice is hemolytic. 



*Cf. Abderhalden, E. Op. cit., S. 22-23. 



t Neuberg, C, and Reicher, C. Lipolyse, Agglutination und Hamolyse, Biochemische Zeitschrift, Band 4, S. 281. 



INeuberg, C, and Rosenberg, E. Lipolyse, Agglutination und Hiimolyse, Berliner klinisehe Wochenschrift, Band 



44, S. 54. 

 Noguchi, H. On certain thermostabile venom activators, The Journal of Experimental Medicine, vol. 8, p. 87. 

 Noguchi, H. Ueber einer lipolytische forme der Hamolyse. Biochemische Zeitschrift, Band 6, S. 184. 

 [Delezenne, C. Comp. rend. d. 1. Soc. Biol. d. Par., T. 55, p. 171 (1903). 

 II U. Friedemann. Deutsche Med. Woch. 1907. 



