242 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Ordi r of arranq, m< nt of experiment* with and without alcohol. — In these experiments two 

 different orders of arrangement have been observed. By one plan the experiments with and 

 without alcohol are separated by a longer or shorter interval, and in each case the experiment 

 proper, during which the subject is in the respiration calorimeter, is preceded by a preliminary 

 period during which he is outside the chamber but has the same or nearly the same diet and 

 exercise. The experiments of Groups A, B, D. CI, and No. 5 of Group H belong to this class. 

 Each of these experiments has continued in the majority of cases for 8 days, the first half being 

 devoted to the preliminary and the other half to the actual experimental period. In some 

 instances, however, the preliminary period was only 3 days. One object of the preliminary 

 period has been to bring the body as nearly into nitrogen equilibrium as practicable. The 

 attempts to secure nitrogen equilibrium by this means have not, on the whole, been successful, 

 a circumstance to which more especial attention is called beyond. 



By the other plan the experiments with and without alcohol follow one another without 

 interruption, thus making really successive periods of a single experiment, or successive 

 experiments of a series. Each such series is preceded by a preliminary experiment, during 

 which the man is not in the chamber, but receives, at least during the latter part of the period, 

 the same diet as in the experiment proper. At the end of the preliminary period the man 

 enters the chamber and remains there during the several periods of the experiments proper. 

 The transitions from one diet to another are thus immediate. The experiments of Groups C, E, F, 

 and I and Nos. 15, 16, and 17 of Group H were of this sort. Since, however, No. 15 was 

 preceded by a preliminary period, and the only differences between Nos. 15, 16, and 17 were 

 in the kind of alcoholic beverage — commercial alcohol, whisky, and brandy — these might be 

 considered one experiment of the first kind. 



Each plan has its advantages and disadvantages. A reason for this is found in the fact that 

 alcohol in moderate quantities appears to have, with some persons, especially with those unac- 

 customed to its use, a special effect upon nitrogen metabolism. It seems probable that this is 

 exercised through the nervous system, that it may for a short time tend to increase the excretion 

 of nitrogen, but that it is, in some cases at an}' rate, only temporary, and disappears after a few 

 days when the permanent effect manifests itself. Accordingly, there is a disadvantage in the 

 second plan, in which the alcohol experiment proper is not preceded by a preliminary period 

 with alcohol diet, in that the persistent effect of the alcohol may not become manifest during the 

 first days of its use in the experiment. Whether, when, or how much this factor may influence 

 a given experiment it is difficult to say. 



On the other hand, there is a disadvantage in the first plan in that, as the experiments with 

 and without alcohol are not consecutive, the body may, during the interval between them, 

 become changed in its capacity or tendency to respond to the different diets. The second plan 

 has the corresponding advantage that differences in the observed results in two consecutive 

 periods might be more clearly due to the diet and less influenced by changes in bodily condition; 

 but here, again, we are dealing with uncertainties. 



To some it might seem that the best test of the effect of alcohol upon nitrogen metabolism 

 would be found in experiments on the first plan, while others would consider those on the second 

 plan more trustworthy. To the writers it seems that experiments on both plans are desirable. 

 Of course the most desirable plan of all would be to continue the experiments through periods long 

 enough to make sure that the normal action of the alcohol appears, and to alternate the alcohol 

 periods with periods without alcohol. This plan has been followed successfully in experiments 

 upon the special question of the protection of protein by alcohol, as explained in the discussion 

 of this subject beyond. 



GROUP A. EXPERIMENTS NOS. 9 AND 10. REST EXPERIMENTS WITH ORDINARY DIET AND WITH 



ALCOHOL DIET. 



The 2 experiments in this group were planned to compare the effects of ordinary diet with 

 those of alcohol diet when the subject did as little mental and muscular work as practicable. The 

 subject, E. O., was the same as in a number of other experiments. The amounts of nutrients 



