330 D. I. MACHT, S. ISAACS AND J. GREENBERG 



In each test twenty numbers were generally employed at each 

 sitting. This method furnished quite a complicated association 

 test and at the same time eliminated as much as possible mem- 

 ory and habituation or familiarity. The subject in every case 

 was expected to go through the mathematical process in his 

 mind and not to rely on his memory at all. Great attention 

 was paid in the association tests to the number of errors made, 

 and these were recorded for comparison of the normal reaction 

 time with that obtained after the administration of a drug. 



SUBSTANCES STUDIED 



After the normal simple and complex reaction times were es- 

 tablished in any one experiment, the subject was given a drug, 

 and the reaction time was then again measured repeatedly at 

 intervals in order to determine the effect of the substance. The 

 effect of the drug was indicated by changes either in the mean 

 reading or by changes in the mean variation between the readings, 

 or by both. In case of association tests the number of errors made 

 in computations, before and after the drug was administered, was 

 also taken into account. Inasmuch as the antipyretic drugs do 

 not lend themselves well to administration by injection, all the 

 drugs were given by mouth under the supervision of Dr. Macht. 



In testing simple reactions to sound, touch and light, the num- 

 ber of readings taken were generally from twenty to fifty or more 

 in each series. In testing the association time, twenty problems 

 were submitted by each method. An average reading was com- 

 puted with the help of a calculating machine, thus saving an enor- 

 mous amount of time, and the mean variations were also com- 

 puted by means of an adding machine, in accordance with Dun- 

 lap's method (4). 



The experiments were performed for the most part on the 

 authors themselves, and occasionally on other subjects. About 

 forty experiments were made in all, each lasting from two to five 

 or more hours. The drugs studied were the following: quinin, 

 acetanilid, acetphenetidin (phenacetin), antipyrin, phenyl salicy- 

 late (salol), acetyl-salicylic acid (aspirin), and pyramidon. In 



