158 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



metabolism which must not be neglected in the interpretation of exper- 

 iments in which it has been taken. It is conceivable that in the earlier 

 experiments with diabetics reported from this laboratory by Benedict 

 and Joslin the small amount of coffee taken by the subject one or 

 two hours before the experiment may have been responsible for a part 

 of the increase noted in the metabolism, although it was at that time 

 specifically stated that the coffee could have no influence. 1 The 

 amount of coffee taken by the diabetics was, however, less than half 

 of the amount given in these experiments, and it was usually taken 

 some time prior to the beginning of the observations. Since Novem- 

 ber 1914, no coffee has been used by the diabetic subjects on the 

 morning of the experiment. 



An examination of the pulse-rate data obtained in the coffee experi- 

 ments shows slight increases after the ingestion of coffee for nearly 

 all of the experiments, with usually a subsequent rapid fall to its previ- 

 ous level. In one experiment, that with L. E. E., March 23, 1911, the 

 rate was lower after the coffee was taken. 



The systolic blood pressure was higher in most instances after the 

 coffee was drunk. The maximum rise was about 20 mm. mercury in 

 the experiment with J. J. C. on March 9, 1911. 



Experiments made by Edsall and Means 2 and Higgins and Means 3 

 on the effect of caffein have an interest in this connection, as they show 

 clearly the influence upon the metabolism of this constituent of coffee. 

 Two experiments were made by Edsall and Means in the Massachusetts 

 General Hospital, both of which indicated a definite although not 

 very great rise in the metabolism. Those made by Higgins and Means, 

 and published from this laboratory, show that with one of the subjects, 

 J. H. M., the gaseous metabolism was markedly increased. With 

 H. L. H. there was also an increase in the metabolism, although this 

 was slight. 



We may conclude, therefore, that coffee, owing probably to its 

 caffein content, acts as a stimulus to the metabolism, the increment 

 with 325 grams of coffee infusion amounting on an average to 8 per 

 cent for several hours. Experiments with caffein-free coffee would 

 therefore have special interest. 



Benedict and Joslin, Carnegie Inst, Wash. Pub. No. 136, 1910, p. 216. 



"Edsall and Means, Arch. Intern. Med., 1914, 14, p. 897. 



'Higgins and Means, Journ. Pharm. and Exp. Therapeutics, 1915, 7, p. 1. 



