12 



In the tables showing the results of the studies all food materials 

 are grouped under 13 general classes, viz, soups, dairy products, 

 cereals, breads, desserts, vegetables, fruits, beverages, combination 

 meals, sugars (ordinary sugar and sirup), meats (including hash, 

 unless otherwise itemized), fish, and eggs. Combination meals appear 

 without l)read and beverages and represent the characteristic part of 

 the meal only. It is the custom at Randall Hall to serve with the com- 

 bination meals several kinds of bread, and tea, coffee, or milk at the 

 option of the individual. Since the size of the portions of bread and 

 the quantity of the beverages are the same as when ordered separatel}^, 

 these may be recorded as if separate from the combination meals and, 

 both for the sake of convenience and in order that the different kinds 

 of food materials might, so far as possible, be grouped according 

 to their respective classes, this method was followed in the tables. 

 The actual value of a com))ination meal as served is greater than would 

 appear from the figures in the tables by the nutrients contained in that 

 particular selection of bread and drink which accompanied the meal; 

 the cost likewise is greater by 2 cents. On the other hand, the figures 

 indicating the nutrients and energy furnished by separate orders of 

 breads and beverages are necessarily too high by the same amount 

 that the combination meals appear too low, and the same applies to the 

 cost. However, it is plain that the matter is simply one of distribu- 

 tion, the tinal value of the ration being, of course, unaffected. 



The data showing the nutritive value of the diet are calculated on 

 the basis of digestible protein and available energ}- in addition to the 

 more usual basis which refers to amounts eaten. The figures for 

 digestible protein and available energy were included and used in the 

 discussion because it was believed that these data could be calculated 

 with reasonable accuracy by means of factors, and that the results so 

 obtained offered a more satisfactor}' basis for comparison and discus- 

 sion than the statistics of quantities eaten. 



The factors or coefficients emplo3'ed for digestibility of protein and 

 availability of energy were deduced from the results of a large num- 

 ber of studies carried on in connection with the nutrition investigations 

 of the Office of Experiment Stations and other similar work, and are 

 given in Table 2 below. Their accuracy, the importance of many of 

 them, the relation between digestible or available nutrients and 

 nutrients eaten, and related topics have been discussed in detail by 

 Atwater" and by Atwater and Bryant,'' and also referred to in earlier 

 bulletins of this series.'" 



The figures show how much of the protein of different foods and 

 food groups is digested — that is, taken up by the body and utilized. 



« Connecticut Storrs Station Rpt. 1899, p. 69. 



''Ibid., p. 73. 



cU. S. Dept. Agr., Offit-e of Experiment Stations Buls. 126, p. 19, and 136, p. 105. 



