194 PSYCHOLOGICAL EFFECTS OF ALCOHOL. 



For satisfactory operation the following precautions and adjustments 

 are necessary: (1) The galvanometer must be connected in series with 

 from 6 to 12 condensers of 2 microfarads each. These serve to eliminate 

 or enormously reduce body-currents and polarization phenomena. 

 (2) The electrodes should be light, flexible, moist, and evenly pressed 

 against the skin by some elastic device that takes up respiration- 

 movements. We found it satisfactory to cover the surface of thin 

 metal plates, about 10 cm. in diameter, with blotting-paper which was 

 saturated with normal salt solution. These electrodes were mounted 

 on a cork and inserted under the clothing. They could be held in place 

 by a thumb-tack, pressed through the clothing and into the cork. A 

 wide elastic band around the body, over the electrodes, kept the con- 

 tact sufficient^ constant when the band was just tight enough to stay 

 in place. 



EFFECT OF ALCOHOL ON THE PULSE-RATE DURING ASSOCIATION 



EXPERIMENTS. 



The pulse-records during the association experiments were made by 

 the electric recording device as described above in method II. They 

 appeared in the kymograph record on a continuous spiral base-line 

 which represented a total experimental period of about 12 minutes. 

 Since the cylinder of the kymograph had a peripheral velocity of 50 mm. 

 per second, each pulse-cycle was from 30 to 60 mm. long on the record, 

 and was read with an average error of 0.005." Each 12-minute record 

 represents an association series of 50 words. The actual duration of 

 each series was usually longer than 12 minutes. There was always a 

 delay of several seconds after the first 25 records to readjust the drum. 

 Occasional delays occurred for taking additional data by Wells and for 

 instrumental adjustments. During these delays the forward pro- 

 gression of the drum was stopped and the spiral record was thus 

 temporarily modified to a circle. Six sets of these records were made 

 in the course of a 3-hour experimental session. The general arrange- 

 ment of the association experiment, as well as the relative position of 

 subjectand experimenter, may be seenfrom figure 21, opposite page 101. 

 On the table, at the subject's left hand, this figure also shows the electric 

 pulse-transmitter, which was connected with the Tigerstedt bulb on 

 the wrist of the subject. A similar transmitter, shown on the stand 

 at the right, was used for respiration-waves. 



A part of a typical kymographic record of the association experiments 

 is shown in figure 30. The entire detached record-sheet would be 

 50 cm. long and contain 1 line for each of the 50 associations which 

 constituted an experimental series. For reproduction we have chosen 

 that section of the record which shows the reaction-time of the associ- 

 ation experiments. If one reads the record from left to right, the 

 small, rhythmically recurring plateaus on each line are pulse-records. 



