On the Decomposition of Caffeine in the Liver. 133 



Half a gram of caffeine was added to a portion of the extract thus 

 obtained, and kept in the thermostat at body temperature for from 

 two to ten days. An equal quantity of the extract without adding 

 caffeine, similarly treated, was used as a control. As indicated in 

 the accompanying table, practically the entire amounts of caffeine 

 were regained. The total quantities of nitrogen found in the pre- 

 cipitated purins were approximately equal save in two experiments 

 in which the amounts of total nitrogen were from 13 to 19 per 

 cent, greater when caffeine was added than in the controls. 



Digestion of liver extracts with and without caffeine in the 

 presence of hydrogen peroxide likewise failed to indicate the pres- 

 ence of a specific enzyme capable of splitting off the methyl group 

 in caffeine. 



Experiments. 



Experiment 

 No. 



Liver extract 

 in c.c. 



Duration of 

 digestion in 

 days. 



Caffeine 

 added. 



Nitrogf n. ^ 



Caffeine 

 regained. 



250 



Two. 



O.S 



0.0699 



0 4935 



250 



Two. 





0.0704 





250 



Four. 



o-S 



0.0660 



0.4921 



250 



Four. 





0.0581 





250 



Eight. 



O.S 



0.0S3I 



0.4915 



250 



Eight. 





0. 0522 





300 



Five. 



0-5 



0.0511 



0.4918 



300 



Five. 





0.0499 





300 



Ten. 



0-5 



0.0604 



0.4799 



300 



Ten. 





0.0496 





250 



Four and 



O.S 



0.0345 



0.4897 





one half. 









250 



Four and 





0.0370 







one half. 









S0O+ 



Four and 



O.S 



0.0416 



0.4951 



5 c.cm. Hj02 



one half. 









500+ 



Four and 





0.0441 





5 c.cm. H2O2 



one half. 









300 



Four. 



O.S 



0.0478 



0.4931 



300 



Four. 



O.S 



0.0432 



0.4952 



300 



Four. 





0. 0444 





' Total nitrogen was determined by E. C. Trescott. 



