382 Prof. H. E. Armstrong and Dr. E. Ormerod. [June 14, 



and dried. This material was used in the following experiments in which 

 03 gramme seed residue, 01 c.c. toluene, 5 grammes castor oil, 3 c.c. 

 lsT/5 acetic acid and 3 c.c. water were digested together. The number of 

 cubic centimetres of N/NaOH required to neutralise the acid liberated 

 during 20 hours was — 



Treatment of seed residue. 



Untreated 14"6 



Alcohol 9-0 



Ethylic butyrate 14"9 



Ethylic acetate 14 - 65 



Ethylic tartrate 11 '3 



Me thy lie sulphate 0'6 



Comparison of Animal with Vegetable Lipase. — Dr. Harden has been good 

 enough to prepare for us at the Lister Institute a quantity of animal lipase, 

 following the directions given by Dakin.* A fresh pig's liver was minced 

 and mixed with Kieselguhr and sand ; the expressed fluid (450 c.c.) — a dark 

 red liquid — was then centrifugalised to remove a small amount of suspended 

 jelly. The fluid was diluted with water in various proportions for the 

 experiments. This lipase acted readily on ethylic butyrate and to a very 

 slight extent on ethylic tartrate. The following results were obtained, using 

 1 c.c. ethereal salt, 50 c.c. lipase solution and - 2 c.c. toluene : — 



Percentage of lipase solution. 



Cubic centimetres of 

 N/5 alkali corresponding 



to acid liberated by 

 enzyme after 48 hours 

 at 25°. 



Percentage 

 hydrolysed. 



Ethylic butyrate — 







5 



35 -2 



90 



2i 



26 -95 



69 



1 



20 -9 



53 



X 



a 



17 "45 



44 



2| + 10 N/5 acetic acid 



20 -05 



51 



Ethylic tartrate — 





gramme. 



5 



2-5 



= -0515 



5 + 10 N/5 acetic acid 



1 -75 



= "036 



The action of the two lipases was contrasted in a series of experiments 

 using mixtures (a) of 1 c.c. of ethereal salt, - 2 c.c. toluene and 50 c.c. of 

 2-per-eent. lipase solution, (b) of 1 c.c. ethereal salt, 5 c.c. N/5 acetic 

 acid, - 2 c.c. toluene, 0*5 gramme castor oil seed residue, water to 50 c.c. 



* ' Journal of Physiology,' vol. 32, p. 202. 



