120 



Effect of Alcohol on Psycho-Physiological Functions. 



ation of the pulse-length after alcohol was considerably smaller than on 

 normal days. It was this consistent change in the mean variation, 

 together with other supporting evidence, which led to the belief that 

 the effect produced by alcohol was probably a partial paralysis of the 

 cardio-inhibitory mechanism. As a rule, the individual pulse cycles 

 were not measured in the data for the repetition experiments on Sub- 

 ject VI, but in the case of the tetanus-pulse records and of those rec- 

 ords taken with the finger movements, the individual cycles were by 

 necessity measured; a mean variation is thus available for these. 



The mean variations for the pulse taken during finger movements 

 have been entered in table 22. Here it will be found that the normal 

 values ranged about 80 cr, approximately 10 per cent of the pulse dura- 

 tion. After alcohol there was a marked decrease, the average for all 

 periods after the dose on the alcohol days being 41 a, with an average 

 pulse duration of 813 a. In terms of per cent differences, the effect of 

 alcohol upon the mean variation of the pulse duration is (section in), 

 beginning with period 2, —20, —37, —21, —17, and —14 per cent, 

 the average for periods 2 to 6 being —34 per cent. 



The mean variations in the pulse-length during pre-tetanus and 

 tetanus are given in table 23 by periods and by days. The average pre- 

 tetanus mean variation for periods 2 to 5 of the normal days is 3.7 hun- 

 dredths of a second and for the alcohol days, 3.0 hundredths of a sec- 

 ond. The average normal tetanus mean variation is 5.7, exclusive of 

 period 1, and that for the alcohol periods is 4.4 hundredths of a second. 

 The decrease in mean variation is particularly prominent in period 2 of 

 alcohol pre-tetanus pulse. Thus these data for the effect of alcohol on 



Table 23. — Mean variation of pulse duration for pre-tetanus and tetanus periods. 

 [Values given in hundredths of a second.] 



