164 PSYCHOLOGICAL EFFECTS OF ALCOHOL. 



SUMMARY OF EYE-MOVEMENT DATA. 



In view of the fact that reliable data on the eye-movements are rela- 

 tively few, and in view also of the peculiar importance of this group of 

 measurements, as will appear in the concluding chapter, it seemed 

 advisable to make the summary as complete as possible. A complete 

 statement of all the averages is consequently given in table 26. In this 

 table appear (1) the average duration of the eye-movements; (2) the 

 average errors; and (3) the average differences, under each of the three 

 headings "Movements to the right," "Movements to the left," and 

 "Total," i. e., the sum of the movements in both directions. In the 

 group of data which is indicated as Normal I and Normal II the aver- 

 ages for both normal days are given in a single column. But the dura- 

 tions for the two days are given separately for each subject, whenever 

 available, connected by a bracket. Similarly the averages at the foot 

 of the columns appear double; the upper ones (99, 101, 201) are the 

 average durations of the eye-movements of the group for the first 

 normal day; the lower ones (102, 109, and 211) are the corresponding 

 values for the second normal day. In giving the "differences" for this 

 group of experiments the two normal days have been averaged, since 

 that is the form in which they will be used in the subsequent tables. 



The summary of the effect of alcohol on the eye-movements is given 

 in tables 27 and 28. In the former, the effect is computed from the 

 averages according to the formula: the average values after alcohol 

 minus the average values of the two normal days equals the effect of 

 alcohol. From table 27 it appears that the average duration after 

 alcohol is almost uniformly greater than the average duration on normal 

 days. In table 28 the effect of alcohol on the various processes is 

 calculated from the "differences." In the left-hand part of the table 

 the effect is stated in average differences; in the right-hand part it is 

 stated in percentile differences. The formulae for the two values are 

 given in footnotes to the respective tables. 



In order not to complicate our main results and obscure their bearing 

 on the main question at issue, we would for the present abstract from 

 the minor questions of ocular balance, the individual differences in the 

 interaction between the internal and external recti, the amount of 

 fixation error, and the number of cycles for the sake of giving greater 

 emphasis to the most general of all the eye-movement data that are 

 given under the heading of "Total." This averages 2.5 per cent after 

 dose A, and 18.6 per cent after dose B. That is to say, after 30 c.c. 

 of alcohol, eye-movements of 40, without regard to the direction, took 

 an average of 2.5 per cent longer time than under normal conditions. 

 Similarly, after 45 c.c. of alcohol, they took an average of 18.6 per cent 

 longer time than the normal. It is conspicuous that in all these values 

 there is only one exception, viz, Subject III after dose A. It is further 

 conspicuous that for all the subjects where there are comparable data, 



