148 PSYCHOLOGICAL EFFECTS OF ALCOHOL. 



MOTOR COORDINATIONS. 



The fundamental technical problem in any attempt to measure the 

 effect of alcohol on human motor coordination must be to discover some 

 measurable and generally practiced motor process whose character 

 and complexity are definitely known, and whose operation is removed 

 as far as possible from the voluntary or capricious control of the subject. 



While the total irritability of nervous arcs is indicated by the latent 

 time of reflex and reaction and by the amount of muscle contraction 

 which follows a definite stimulus, neither of these measurements gives 

 any indication with respect to the adequacy of the central elaboration 

 of the response. As far as our present knowledge goes, we can not 

 regard the adequacy of any simple human reflex as a measurable 

 quality. It would be possible, however, to find an indication of the 

 adequacy of coordination in any one of the more complex reaction 

 processes if we had suitable techniques. For example, the accuracy 

 of fixation in the reactive eye-movements would depend on the ade- 

 quacy of the oculo-motor coordinations. But unfortunately, as we 

 have pointed out, accurate spatial measurements of the eye-movements 

 present many technical difficulties that are not met in time measure- 

 ments. For the present experiments, at least, these difficulties seemed 

 to make measurement of the adequacy of visual fixation impracticable. 

 Similarly, the sequence of movements that are involved in speech, as 

 it occurs in word-reactions, would be an excellent indication of the 

 adequacy of a generally practiced coordination process. Such an 

 indication would be of peculiar value in experiments with small doses of 

 alcohol, since there is evidence in the disturbed utterance of patients 

 suffering from acute alcoholism that large amounts of alcohol notably 

 affect the coordinations of speech. But in the case of speech, even more 

 conspicuously than in the case of the eye reactions, the difficulties of ade- 

 quate registration and measurement are at present prohibitive. Meas- 

 urements of the effect of alcohol on the coordinations of speech would be 

 further complicated by the wide variations of normal pronunciation. 



Much the same difficulty would appear to threaten the attempt to 

 measure the motor coordination in standing, walking, writing, etc. In 

 the more consciously controlled processes of drawing, typewriting, 

 typesetting, etc., new technical difficulties appear in the unknown 

 and unmeasured interplay of interest and effort and the complex 

 group of determinants that we commonly call the will. Such meas- 

 urements are especially useful as an indication of the effect of alcohol 

 on socially important processes, but their scientific value would be con- 

 ditioned by a knowledge of the interaction of the several factors that 

 combine to produce any specific performance in these processes. 



When we attempt to analyze out of human action the simplest form 

 of motor coordination, which corresponds, in its relation to complex 

 acts, to the relation between the simple reflexes and the complex 



