1919] FOODS HUMAN NUTRITION. 861 



methods of analysis along with sufficient discussion on the literature of the 

 subject to show the history and derivation of these methods. Material has 

 been taken freely from the reported investigations and each chapter con- 

 tains numerous references to the literature on the subject. The subject ma- 

 terial is considered under the following lieads : 



Bacteriological apparatus ; media and their preparation ; stajning technique 

 and microscopic methods ; classification and description of bacteria ; steriliza- 

 tion and disinfection ; proteins, carbohydrates, and fats ; yeasts and molds ; in- 

 testinal bacteria ; bacterial examination of air ; water hygiene ; milk and milk 

 products ; bacteriology of eggs ; meat and meat products ; food preservation ; 

 and epidemiology. 



The book contains much illustrative material, including eight colored plates 

 on the candled and opened appearance of market eggs. 



The relative digestibility of our food materials, M. Rlbner {Berlin. Klin. 

 Wchnschr., 55 (1918), No. 47, pp. 1113-1119).— The author points out certain 

 features in the estimation of the nutritive value of foods which in his opinion 

 need to be taken into consideration, with consequent revision of values. Among 

 the points discussed are the proportion of protein in different nitrogen-con- 

 taining substances, the amount of indigestible pentoses and celluloses in carbo- 

 hydrates, the relative value and digestibility of mixtures of foods of vegetable 

 and animal origin, individual idiosyncrasies, the palatability of foods, and 

 satiety. 



Digestibility of our food, M. Rubneb (Umschau, 22 (1918), No. 51, pp. 671- 

 676). — A resume of the article noted above. 



Fats and fatty acids as food (Jour. Physiol, 52 (1919), No. 5, pp. 328-346).— 

 Five papers are presented. 



I. Introductory, W, D. Halliburton and D. N. Paton (pp. 328-330).— A brief 

 outline is given of the purpose of the investigation, which was to determine 

 the possibility during the shortage in the supply of fats of utilizing as human 

 food the fatty acids obtained from fats in the preparation of glycerol for the 

 manufacture of explosives. 



II. Preparations from oils, J. C. Drumniond (pp. 330-333). — An investigation 

 of various sources of fatty acids led to the conclusion that the most suitable for 

 study were those obtained from hardened whale or seal oil, hardened palm or 

 palm-kernel oil, and hardened " soy-cot " oil, the latter a mixture of palm- 

 kernel, soy-bean, and cottonseed oil. An addendum by W. D. Halliburton 

 mentions the impurities which may be present in hardened fats, including 

 nickel and arsenic, both of which under ordinary conditions are present in so 

 small amounts as to be harmless. 



III. Feeding experiments on man, D. Burns and J. S. Sharpe (pp. 333-339). — 

 Hardened whale oil and the fatty acids obtained from it were used in compara- 

 tive feeding experiments from which the following conclusions were drawn : 



*' The fatty acids of hardened whale oil in amounts of 36 gm. per diem, or 

 more than one-third of the usual intake of fat, wei-e as thoroughly digested 

 and absorbed as was the hardened oil from which they were prepared. Their 

 administration for a period of six days caused no disturbance in the absorp- 

 tion of the other constituents of the food as is indicated by the nitrogen and 

 energy balances, nor any other disturbance in health. They may, therefore, be 

 used as a source of fat in the diet of man." 



IV. Feeding experiments on aninmls, J. C. Drummond and W. D. Halli- 

 burton (pp. 339-343). — The effect of the three fatty acids on maintenance and 

 growth in rats was studied, and the following conclusions were drawn : 



" There is no toxic action excited by an admixture of from 5 to 10 per cent 

 fatty acids of the three fats used. The animals on such a diet take their food 



