238 



PSYCHOLOGICAL EFFECTS OF ALCOHOL. 



This change was so marked and consistent in this subject, and in 

 several others that were sampled, that we reviewed the whole pulse data 

 to collect the mean variations of the pulse-cycles of each record. The 

 pulse-changes that commonly occur within the limits of our 12" records 

 are on the one hand the respiration rhythms, and on the other hand 

 such arrhythmic changes as are produced by the experimental processes. 

 In both cases the long cardio-accelerator latency obviously precludes 

 the accelerator mechanism from participation in these short rhythmic 

 and arrhythmic changes in the pulse frequency. Consistent change in 

 the mean variation of the pulse or its absence seemed to us to be a most 

 important indicator of the responsiveness of the cardie-inhibitor 

 mechanism. The relevant data are collected in table 44 and sum- 

 marized with respect to the influence of alcohol in table 45. 



TABLE 45. Summary of the effect of alcohol on the mean variation of the pulse-cycles. 



Notwithstanding large individual variations, and considerable vari- 

 ability in records from the same individual, which follow inevitably 

 from the varying conditions under which the records were taken, the 

 average changes, which alone are significant, indicate a persistent 

 tendency for alcohol to diminish the mean variation of the pulse-cycles 

 within the limits of our "sample" records. In only one instance, 

 finger-movements after dose A, is the average mean variation larger 

 after alcohol than on the normal days, and in this case the percentile 

 change is conspicuously small. The average decrease in the mean 

 variation of the pulse-cycles after alcohol is 19 per cent. It should be 

 noted that these percentages are based on the entire pulse-cycle, and 

 not on the diastole, as in the discussion of the relative changes in systole 

 and diastole of Subject III. 



It may be held that the smaller mean variation after alcohol is due 

 to the relative acceleration of the pulse after alcohol. This could not 

 explain it. The changes in mean variation are absolute, not relative, 

 and occur even in those cases in which there is no absolute acceleration. 

 Moreover, the average acceleration was only 3 per cent (p. 231), while 

 the average decreased mean variation is 19 per cent. The decreased 



