June 23, 1922J 



SCIENCE 



661 



of the nature of the diet on the digestibility of 

 butter. Eubner, in a lengthy series of experi- 

 ments, reports three different values for the 

 digestibility of butter — for a simple diet of 

 butter and potatoes'^ 96.3 per cent., for a diet 

 of green beans and butter- 91.5 per cent., and 

 for the latter diet with a larger portion of 

 butter^ 97.3 per cent. 



Malfatti studied a diet of polenta (a por- 

 ridge of Indian corn meal) and butter and 

 found that butter was 97.7 per cent, digested.* 

 Mayer determined the digestibility of butter" 

 eaten as a part of a simple diet and reports 

 98 per cent, and 97 per cent, respectively as an 

 average of three periods of three days each 

 with a mature subject and a nine year old boy. 

 Atwater conducted digestion experiments on a 

 diet of fish and butter and found the butter^ 

 to be 91 per cent, digested. Huldgren and 

 Landergren, who served as their own subjects, 

 found the digestibility of butter,' eaten in con- 

 junction with hard rye bread, was 95.4 per 

 cent. Luhrig studied the digestibility of butter^ 

 served with a basal ration of meal, bread and 

 vegetables and reports a digestibility of 96 

 per cent, for butter. Von Gerlach determined 

 the digestibility of butter" when it was eaten 

 with a basal ration of rice, zweibaek and oat- 

 meal and found it to be 97 per cent, digested. 

 Since in the metabolism experiments noted 

 above that are not uniform there are many 

 factors, such as food, habits, occupations, and 

 races of people employed as subjects, it is un- 

 wise to attempt to generalize to any extent on 

 the effect of the nature of the diet on the 

 digestibility of butter. 



However, in view of the very general and 

 wide spread use of dairy butter in conjunc- 



iZtschr. Biol., 15 (1879), No. 1, pp. 136-147. 



2 idem., 16 (1880), No. 1, p. 127. 



sidem., 15 (1879), No. 1, pp. 174-176. 



* Sitzber, K., Akad. Wiss. (Vienna) Math. 

 Naturw. El, 90 (1884), III, No. 5, pp. 328-335. 



'iLandw. Vers. Stat. 29 (1883), pp. 215-232. 



BZtschr. Biol., 24 (1887), No. 1, p. 16. 



■! Skand. Arch. Physiol, 2 (1890), No. 4-5, pp. 

 373-393. 



8 Ztschr. Untersuch. Nahr. «. Geniissir.t!., 2 

 (1899), No. 6, pp. 484-506. 



Ztschr, Phys. u. Didtet: Ther. 12 (1908.9), 

 No. 2, pp. 102-110. 



tion with many kinds of food materials, it 

 appears of interest to summarize briefly a 

 number of digestion experiments in which 

 butter has been included as a part of the 

 experimental ration and which have been con- 

 ducted under identical experimental conditions, 

 as regards the type of subjects, the length of 

 experimental period, and methods of chemical 

 analysis. In many of the digestion experi- 

 ments conducted by the writer to determine the 

 digestibility of cereals, legumes, meats, vegeta- 

 bles and flours, butter has been employed as a 

 source of fat for the experimental diet. The 

 butter included in the experimental rations was 

 uniform in that it was always obtained from 

 the same source. Since the digestion experi- 

 ments considered here were made during a 

 period of four or five years, no attempt was 

 made to use a single lot of butter for the entire 

 series of experiments, but it is believed that 

 this butter obtained from a single creamery and 

 presumably from a constant source of milk 

 supply was typical of the ordinary commercial 

 butter purchased by the average consumer. 



The table on p. 662 contains the data essen- 

 tial for the consideration of these experiments 

 and the text which follows includes a discussion 

 of the details of the different types of diets. 



The first group of experiments referred to in 

 the table, eight in which dairy butter was 

 the food material studied, are discussed in 

 detail in the initial paper'^" of a series which 

 has appeared from time to time reporting the 

 results of digestion experiments conducted to 

 determine the digestibility of a large number 

 of edible fats and oils. To secure data con- 

 cerning the relative digestibility of edible fats 

 and oils several digestion experiments with 

 each of the fats studied were conducted under 

 uniform conditions. The experimental ration 

 consisted of commercial wheat biscuit, fruit, 

 sugar, tea or coffee and a special cornstarch 

 pudding or blancmange in which was incor- 

 porated the fat under consideration. In order 

 to mask any noticeable flavor or odor of the 

 fats studied, the blancmange was heavily fla- 

 vored with caramel which gave a uniform char- 

 acteristic caramel flavor and odor to all the 



1" "Digestibility of Some Animal Fats," U. S. 

 Dept. Agri. Bui, 310 (1915), pp. 22. 



