22 PSYCHOLOGICAL EFFECTS OF ALCOHOL. 



CONTROL MIXTURES. 



As our program indicated (Appendix I, p. 272) we were unmindful 

 neither of the advisability nor of the difficulty of preparing a suitable 

 control mixture to be used on normal days in place of the dose of alcohol. 

 Since the discussion of Rivers, 1 the regular use of control doses has 

 become a touchstone of accuracy in psycho-physiological experiments 

 with drugs. The function of the control mixture is to prevent the 

 subject's knowing which are normal and which are alcohol sessions. 

 As Rivers himself notes, such control doses are relatively easy to pre- 

 pare in the case of caffein and relatively difficult in the case of alcohol. 

 The difficulty in the case of alcohol became more and more apparent 

 as our preparations progressed. 



With the help of the various chemists of the Nutrition Laboratory, 

 and the advice of a number of physiologists, a variety of possible 

 control mixtures were considered. A number of these, including the 

 preparation advised by Rivers, 2 were tried on ourselves and other 

 members of the Laboratory staff. None of them proved to be entirely 

 satisfactory. In every case the alcohol mixture of a concentration 

 anywhere approximating 20 per cent could always be detected by com- 

 petent observers, even when the flavoring was sufficiently strong to 

 raise serious questions as to its pharmaceutical indifference. Wiping 

 the rim of the glass which contained the control mixture with alcohol 

 introduced a somewhat confusing discrepancy between smell and taste, 

 but the alcohol "taste," its peculiar stinging warmth, was never even 

 approximately masked. If enough capsicum were put into the control 

 dose to produce a sting at all comparable to that of the alcohol, it was 

 conspicuously different in its subjective after-effects. But even then 

 the control dose seemed flat. 



In those cases where the administration of control mixtures seemed 

 imperative, i. e., for the psychopathic subjects, we used Rivers's mix- 

 ture, substituting 1 c.c. strong infusion of quassia for the capsicum. 

 We substituted the quassia for the capsicum because of its pharma- 

 ceutical indifference and because of the general capacity of a strong 

 bitter to cover other tastes. The mixture has good precedents; quassia 

 was used by Zimmerberg, 3 and by Von der Muhll and Jaquet. 4 It 

 produces a medicine-like taste which apparently distracts the attention 

 from the other ingredients. While in these experiments none of the 



Divers, The Influence of Alcohol and Other Drugs on Fatigue, London, 1908. 

 2 Coneerning his recent experience with the control mixture Professor Rivers kindly gave us 

 information by letter. The control finally adopted by him is as follows: 



Concentrated compound infusion of orange 0.5 drachm. 



Elixir saccharine 1 minim. 



Alcohol or water 1 ounce. 



Liquor capsici to taste. 



3 Zimmerberg, Untersuchungen iiber den Einfluss des Alkohols auf die Thatigkeit 

 Dissertation. Dorpat, 1869. 



4 Von der Miihll nrnl Jaquet, ( 'nrrcsp.-Hiatt f. schweizor Aerzto, 1891, 21. p. 1.57. 



