In considering the changes in the rate of proteid metabolism shown by all the members of this group, it will suffice for present purposes to deal mainly with the average results. Compare now the average daily output of nitrogen through the urine from November 1 until April 4—a period of five months—of each of these men. AVERAGE DAILY OUTPUT OF NITROGEN. Morris 7.03 ⎫ Steltz 7.13 ⎪ Broyles 7.26 ⎪ Loewenthal 7.38 ⎪ Oakman 7.42 ⎪ Fritz 7.84 ⎬ = 7.80 grams Nitrogen as Cohn 8.05 ⎪ the grand average. Coffman 8.17 ⎪ Zooman 8.25 ⎪ Sliney 8.39 ⎪ Henderson 8.91 ⎭ Bates 8.08—Oct. 27-Feb. 11. Davis 8.61—Oct. 26-Jan. 12. The figures given show an astonishingly low proteid metabolism for the five months’ period; 7.5 grams of nitrogen in the day’s urine correspond to 46.8 grams of proteid metabolized, while 8.5 grams of nitrogen mean the metabolism of 53.1 grams of proteid. In other words, all of these men during a period of five months practically averaged a daily output of nitrogen through the kidneys corresponding to the metabolism of less than one-half the 105 grams of absorbable proteid called for by the so-called standard diets. Further, close scrutiny of the results in the individual tables shows that during many weeks much lower results were obtained than is indicated by the general averages. Just here emphasis should be laid upon one fact, doubtless of primary importance in any modification of the rate or extent of metabolism in any individual, viz., that in this experiment the daily diet was prescribed, thereby taking from the individual freedom of choice in the selection of food. The writer has no question in his own mind that an intelligent choice of food, coupled with the satisfying of a natural or acquired appetite in moderation, will lead to better results than any system of prescription as to what shall be eaten each day and in what quantity. Still, this is the method necessarily made use of in the present experiment, the writer having prescribed the character and amount of each meal throughout the entire six months’ period, with due regard, of course, to the expressed likes and dislikes of the men.