206 PSYCHOLOGICAL EFFECTS OF ALCOHOL. 



the succeeding periods. This whole picture of the pulse adaptation 

 in successive periods of the same session and in the first period of 

 successive sessions is a direct analogue to the familiar laws of habit 

 formation, and corresponds with the large practice effect that was 

 actually found to occur in the association experiments (Chapter IV). 



Another conspicuous difference in the pulse-reactions on the first 

 and last day is the longer duration of the experimental disturbance 

 on the former. This again is probably an adaptation phenomenon. 



To recur to the apparent effect of alcohol on the association pulse, 

 figure 31 makes it clear that gradually increasing pulse-retardation 

 from the beginning to the end of the session is a distinct and character- 

 istic feature of the normal days. The second normal day starts at a 

 slightly different level from the first, but the total relaxation change is 

 practically the same in both days. It is exactly this gradual relaxation 

 which is most obviously modified in the curves for the alcohol pulse. 

 After dose A there is still an increase in the average duration of the 

 pulse-cycles, but it is distinctly less than on the normal days. After 

 dose B, this increase in duration gives place, after the third period of 

 the day, to an irregular decrease. A further conspicuous effect of the 

 larger dose is almost to annihilate the experimental rhythm. 



These pulse-changes in Subject VII are too systematically related 

 and too clearly marked to be accidental, but only a few of them are 

 general with the group. While there are points of agreement, several 

 subjects seemed to show more or less persistent pulse-changes in the 

 association test which are purely individual. For some of them, the 

 course of the pulse was quite irregular. Subject VII shows the most 

 pronounced experimental change. Subject IX (a native German), who 

 had considerable difficulty with the association test, shows peculiarly 

 long and relatively large post-stimulation acceleration. 



The data of association pulse-changes for all the subjects except 

 Subject VII, which has already been given in the preceding table, are 

 given in table 36. As hi table 35, each average represents about 50 

 pulse-cycles hi a corresponding phase of the association experiment. 

 All averages are given in 0.01". The number or letter in the first 

 column designates the series of association words as described in 

 Chapter VI. 



Inspection of tables 35 and 36 shows that the pulse of all the subjects 

 is accelerated more or less in the post-stimulation phase of the associ- 

 ation experiments. For all subjects, moreover, the post-stimulation 

 pulse-acceleration is greatest on the first normal day. The same kind 

 of adaptation process that appeared conspicuously in the pulse-records 

 of Subject VII appears in the records of all the subjects to some degree. 

 Subjects II, X, and III show a rapid return of the pre-stimulation 

 pulse-length immediately after reaction. 



The average post-stimulation acceleration of the pulse is shown in 

 table 37, for both the normal and the alcohol experiments, by the aver- 



