868 EXPERIMENT STATION EECOED. [Vol. 38 



digestibility of fats and oils (E. S. R., 36, p. 860), data regarding tlie diges- 

 tibility of almond, black-walnut, Brazil-nut, butternut, English-walnut, hickory- 

 nut, and pecan oils are reported. As in the former experiments, normal young 

 men served as subjects and the nut oils studied were incorporated in a basal 

 ration. The results are summarized as follows: 



An average of 70 gm. of almond, 56 gm. of black-walnut, 81 gm. of Brazil-nut, 

 43 gm. of butternut, 78 gm. of English-walnut, 95 gm. of hickory-nut. and 104 

 gm. of pecan oil was eaten per subject per day in the experiments, out of a total 

 of 71 gm., 68 gm., 84 gm., 46 gm., 80 gm., 97 gm., and 107 gm. of fat supplied by 

 the respective diets. The oils were found to be well digested, the coefficients of 

 digestibility being 97.1 per cent for almond oil, 97.5 per cent for black-walnut 

 oil, 96.3 per cent for Brazil-nut oil, 95.4 per cent for butternut oil, 97.6 per cent 

 for English-walnut oil, 99.3 per cent for hickory-nut oil, and 96.8 per cent for 

 pecan oil. 



The nut oils, which are liquid at ordinary temperatures, thus have prac- 

 tically the same digestibility as the common vegetable oils (cottonseed, peanut, 

 olive, sesame, and coconut oils), which are also liquid at ordinary temperatures. 

 While in these experiments as much as 81 gm. of almond oil, 64 gm. of black- 

 walnut oil, 100 gm. of Brazil-nut oil, 49 gm. of butternut oil, 109 gm. of hickory- 

 nut oil, and 130 gm. of pecan oil were eaten per day by one of the subjects for 

 a 3-day test period, no laxative effect was noted; accordingly the limits of 

 tolerance for these fats seems in excess of these amounts. In the experiments 

 with English-walnut oil the three subjects ate 69.9 gm., 83.8 gm., and 81.6 gm. 

 per day, and all reported a slight laxative effect. 



The values obtained for the digestibility of the protein and carbohydrates in 

 the simple mixed diet eaten in conjunction with the different nut oils were in 

 agreement with those obtained in the earlier experiments of this series, indicat- 

 ing that the nut oils did not exert any unusual influence on the digestibility of 

 the foods eaten with them. 



" The results of this study of the digestibility of these nut oils indicate that 

 they are very well assimilated by the human body, and that whenever available 

 they could be used freely for food purposes." 



Bacteria in ice cream. — II, B. W. Hammer and E. P. Goss (Iowa Sta. Bui. 

 174 H^n), PP- ^1)- — ^ continuation of the study of bacteria in ice cream 

 (E. S. R., 28, p. 166) is reported. The following conclusions were reached by 

 the authors : 



" The freezer may be an important source of contamination where an effort 

 is being made to produce ice cream with a low bacterial count, and accordingly 

 considerable attention should be given its care. Water sherbets contain but 

 few bacteria compared to the number ordinarily found in ice cream. The 

 counts on 17 samples ranged from 6 to 7,800 per cc. Ice cream other than 

 vanilla ordinarily contain large numbers of bacteria. The counts on 13 sam- 

 ples ranged from 130,000 to 40,850,000 per cc. There is no evidence that there 

 is an increase in the numbers of contained organisms during the proper stor- 

 age of ice cream while commonly there is a decrease. These results apply to 

 the organisms developing on agar held at 37° C. for 48 hours. 



" There is an apparent increase in the number of bacteria as determined 

 by the plate method during the freezing of ice cream. This is apparently due 

 to the breaking up of the clumps of organisms as a result of the agitation in 

 the freezer. There is usually a decrease in the number of bacteria in ice cream 

 during the hardening process, pre.sumably as a consequence of the destructive 

 action of the lowered temperatures. 



" The softening and rehardening of ice cream may result in a significant 

 increase or in a decrease in the number of bacteria contained. The effect is 



