I 



SOME MATTERS OF GENERAL HYGIENE 221 



experimental studies have consistently shown that caffein 

 is a true stimulant, actually increasing the capacity for 

 muscular and mental work. The advisability of resorting 

 to a stimulant must depend largely upon the extent of the 

 after-effect and upon possible cumulative injury. 



A most painstaking investigation of the properties .of 

 caffein was reported recently by Hollingworth. 1 It was 

 conducted upon a considerable scale, a staff of 7 trained 

 workers gathering data from 16 subjects (of whom 10 were 

 men and 6 women). In all trials of this kind it is neces- 

 sary to keep the subjects in ignorance of the times at which 

 they receive the drug to be tested. Hollingworth gave 

 them at intervals gelatin capsules many of which were 

 blanks, while others contained measured doses of caffein. 

 The heaviest dose equalled the quantity in two large cups 

 of coffee. Ingenious tests were made as a matter of daily 

 routine, whether the caffein was given or not. Speed, 

 dexterity, discrimination, and mental alertness were 

 observed. 



The results of the research were almost entirely favor- 

 able to caffein. Gains were recorded in all the capacities 

 investigated. The tests made with the typewriter were 

 of the most practical interest. When caffein had been 

 received by the worker the copying was accomplished 

 somewhat more rapidly and with fewer errors than at 

 other times. Moreover, when mistakes were made, they 

 were more often recognized on the instant. It is instruc- 

 tive to compare these facts with those that have been 

 secured with alcohol. Both alcohol and caffein probably 

 inspire the user with confidence in his ability to do his best. 

 But there is a divergence in the actual performance, 

 alcohol failing to give the promised reinforcement, and 

 caffein confirming the subjective impression quite deci- 

 sively. 



We naturally assume that a period of stimulation will 

 be followed by one of corresponding depression, as the 



1 "Archives of Psychology," The Science Press, New York, 

 April, 1912. 



