76 Effect of Alcohol on Psycho-Physiological Functions. 



ence to included secondary resistance was not reversed, since the tissue 

 resistance decreases during the first four or five minutes after the immer- 

 sion of the finger-tips in the electrodes. Our first measurement should 

 have been with the 40,000 ohms included in the secondary circuit, and 

 the last measurement with the tissue only in the circuit followed by 

 the Wheatstone-bridge measurements of tissue resistance, which in the 

 test always came last. Thus, any change in tissue resistance would not 

 have exercised so large an effect on the first threshold values taken. 1 



While the measurement of tissue resistance is thus admittedly poor 

 and the procedure is not without fault, yet the routine from period to 

 period and from day to day in these experiments was always the same. 

 Hence, the value of the results for a comparison of the alcohol and non- 

 alcohol days should not be much impaired. The data and results are 

 incorporated in table 13, which presents them by periods, the table 

 being divided into sections according to the usual form. In order to 

 have data which compare directly with those presented by Dodge and 

 Benedict for Subject VI, values for Z have been included in the table. 2 

 Since with the technique used threshold determinations were not mul- 

 tiplied within the period, no mean variations are given or figures for 

 probable correctness of differences. 



The averages for normal days to be found in section i in the last two 

 columns of the table, and which exclude period 1, give the impression 

 that there was the reverse of a practice effect. The number of /3 units 

 required to stimulate increased from day to day. 3 But this is not evi- 

 dent in the thresholds for period 1. The values for the normal days 

 average 356 Z or 184 units. This average is perhaps somewhat larger 

 than would be expected for Subject VI from the data given by Dodge 

 and Benedict in their table 22 for normal days October 7, 1913, and 

 March 2, 1914. It is thus to be observed that the use of the mechani- 

 cally operating key with more rapid rythmical shocks did not serve to 

 reduce the threshold current strength. The average of 184 for (3 is not, 

 however, conspicuously large when compared to the values reported by 

 Dodge and Benedict for some other of their normal subjects. The fact 

 that Grabfield, 4 in determining the average threshold for 135 psycho- 

 pathic cases, found the average to lie at 223 /3 and came to the conclu- 

 sion that a threshold greater than 175/3 may be considered as definitely 

 pathological, can only be interpreted as indicating a difference between 

 the apparatus or technique employed by him and that used at the 

 Nutrition Laboratory. 



i Grabfield (Boston Med. and Surg. Journ., 1914, 171, p. 883) as9umed a tissue resistance of 

 2,100 ohms and omitted the measurement entirely. # 



2 See Dodge and Benedict's report, p. 140, table 22, Subject VI, October 7 and 14. It is under- 

 stood that the Z values given here, as in our table, are the threshold measurements, with tissue resist- 

 ance only included in the secondary circuit. 



8 Martin, Withington, and Putnam, Am. Journ. Physiol., 1914, 34, p. 97. 



4 Grabfield, Boston Med. and Surg. Journ., 1914, 171, p. 883. 



