20 DAVID I. MACHT AND SHACHNE ISAACS 



processes and more particularly on the reaction time in man. 

 Accordingly the present investigation was undertaken 



A search through the literature revealed but two contributions 

 of any importance on the subject. In 1878 Dietl and Vintschgau 

 (6) studied the effects of wine and coffee on the reaction time; 

 observations were made on the authors themselves and in con- 

 nection with the effects of alcohol and caffeine, a few experi- 

 ments were made with morphin. The apparatus for measuring 

 time used by the authors was a rapidly revolving kymograph 

 an obviously inadequate instrument for the purpose. These 

 authors concluded that morphin prolongs the reaction time, but 

 that the effect is of short duration. 



E. Kraepelin (7) in 1892 made some observations on the 

 effects of a number of poisons including alcohol and morphin 

 on the reaction time, and that author found that morphin pro- 

 duced a primary quickening and secondary prolongation of the 

 reaction time in his subjects. 



The present investigation was undertaken with two purposes 

 in view. In the first place, it was desired to ascertain the 

 effect of morphin alone on simple and complex or association 

 reaction time. In the second place, it was desired also to ascer- 

 tain the effect on the. reaction time of the same quantities of 

 morphin when given in combination with other opium alkaloids. 

 Recent pharmacological work has emphasized the importance of 

 what is spoken of as "synergism" of drugs. It has been found 

 that by combining two different substances, a pharmacological 

 effect can be produced which is different from the arithmetical 

 summation of the effects of its two components, as known from 

 their action when administered separately. The two drugs in 

 such a case are said to " potentiate" each other. Thus, for in- 

 stance, one of the present authors (M.) has shown that morphin 

 administered in the form of opium (i.e., in combination with the 

 so-called minor opium alkaloids) is much less depressing to the 

 respiration than when given in the same quantity alone (8). 

 Again, Macht, Herman and Levy (9) have shown that the 

 analgesic power of morphin is potentiated or enhanced by com- 

 bining it with the otherwise inert opium alkaloid, narcotin. 



