SUMMARIES AND CORRELATIONS. 253 



depression with slightly larger doses. It seems probable, too, that we 

 have herewith come upon the grounds for a wide variety of effects which 

 are commonly observed in the social use of alcohol, when circumstances 

 give the reinforcement and alcohol reduces the inhibitions. 



Whatever may be the effect in isolated tissue, our data give clear and 

 consistent indications that the apparent alcoholic depression of neuro- 

 muscular processes is a genii-ne phenomenon that can not be reduced to 

 the excitation of inhibitory processes; but that, conversely, whenever 

 apparent excitation occurs as a result of alcohol it is either demon- 

 strably (pulse-rate, reflexes, memory, and threshold) or probably (eye- 

 reaction) due to a relatively overbalancing depression of the controlling 

 and inhibitory processes. 



IS ALCOHOLIC DEPRESSION A CONSERVATIVE PROCESS? 



One factor in our related group of measurements was expressly intro- 

 duced for its indication of general physiological conditions. That 

 factor is the pulse-rate. There are grounds for believing that the pulse- 

 rate is the best index of the general metabolic demands that is available 

 in psychological experiments (Dodge 1 ). 



It would doubtless be better if the psychological experiments could 

 be carried out coincidently with respiration experiments, or some other 

 means for determining total metabolism during the mental activity. 

 Such an arrangement, however, would present the greatest technical 

 difficulties both from the standpoint of the psychological experiments 

 and from the standpoint of total metabolism experiments. With 

 respect to the psychological experiments, it would be a questionable 

 procedure to add the insistently obvious and not too comfortable 

 attachments for respiration experiments in the expectation of getting 

 natural psychological reactions. With respect to the metabolic experi- 

 ments, it would not be easy to arrange a technique to measure the 

 differential metabolism for the few minutes that are involved in the 

 psychological experiments. Probably both difficulties could be over- 

 come by sufficient sacrifice of time and money, but the satisfactory 

 simultaneous operation of the two elaborate techniques would always 

 be a difficult task. Fortunately for provisional experiments, at least, 

 there are scientific grounds for believing that changes in general 

 metabolism are indicated by the pulse-rate. 



The experience of the Nutrition Laboratory in its studies of the 

 relationship between pulse-rate and metabolism is best expressed by 

 the following quotations: 



"A comparison of this pulse-rate with the total heat-production shows a 

 striking uniformity in fluctuations and similar comparisons with other experi- 

 ments show in nearly every instance a parallelism." 2 



, Psychol. Review, 1913, 20, p. 1. 

 2 Benedict, The Influence of Inanition on Metabolism, Carnegie Inst. Wash. Pub. No. 77, 1907, 

 p. 488. 



