FOODS HUMAN NUTRITION . 67 



In tho otli(>r i* diets tho anioiint of protoin and onorgy was snflifient for the 

 maintenance of health and nniseular vigor, but tlie cost was considerably in 

 excess of " that for which the laboring classes in town or country are able to 

 jtrocurc an c(|nally satisfactory diet." 



"Till' study of the ordinary diets of the laboring classes in all countries seems 

 to show that whenever possible a diet is secured which will yi(>ld soni(>thing 

 over :?,()()(» calories of energy and ov(>r 100 gm. of proteids per man per diem. 

 It is improliable that so many different races should have made the same mis- 

 takes in the essential elements of th(Mr very varied diets." 



Results of digestion expei'inients with milk powder, V. Krult, (Milclnr. 

 Zcntbl., 2 {Willi), yo. //, pp. l(hj-.n.3). — A summary of analytical data and the 

 results of artificial and natural digestion experiments led the author to conclude 

 that milk powder is readily and thoroughly digested and may be used in infant 

 feeding and in the household in many ways. 



Nitrogenous metabolism in normal individuals, J. M. Hamill and S. B. 

 ScHBYVEK (Joiir. I'Jii/.siol., 3.'i (1006), Xo. 3, Proc. PJii/sioL Soc, 1906, pp. Y- 

 XII). — Six-day experiments with 7 subjects showed that on an average the ni- 

 trogen excreted per day was 13.5 gm. Allowing for a loss of 10 per cent in tho 

 feces, this is equivalent to O.S gm. of protein per person per day. The ratio of 

 uric-acid nitrogen to total nitrogen was fairly constant, being 1.-54 on an average. 



Carbohydrate combustion in the animal body, J. Stoklasa (Brr. Dent. 

 Vhciu. (i€>ieU., .3S {190.')), 'No. 2, pp. tiO'i-GlO). — Studies of the effect of expressed 

 meat juice on carbohydrates led to the conclusion that the energy -yielding proc- 

 esses in cell i)rotoplasm are brought about by the enzym lactolase which forms 

 lactic acid from Ciirbohydrates, and by alcoholase, which forms alcohol and car- 

 bon dioxid. The secondary products which are formed by further cleavage are 

 produced only when oygen is present. The enzyms which cause such cleavage 

 are acetolase and formilase. The cleavage products capable of oxidation are 

 converted into carbon dioxid and water by the oxygen of the air. 



The chemistry of digestion in the animal body. Ill, Proteid cleavage 

 in the digestive tract, E. S. London {Ztschr. Phi/siol. Che)ii.. .'/7' {1906), Xo. 

 '1-6. pp. 36S-.^1'}). — In the middle portion of the small intestine alanin and as- 

 partie acid were noted as cleavage products in addition to those reported by 

 other observers when meat was fed. The experiments ^vere made with dogs. 

 The author believes that it is possible to determine proteid cleavage quantita- 

 tively in the animal body, and that Fischer's ester methods may be iised with 

 good results in studying products of animal digestion. 



Concerning the extractive material of muscular tissue. Ill, Methyl- 

 guanidin, W. (Jii.ewitsch {Ztschr. Physiol, ('hem., .'/7 {1906). \o. 'i-6. pp. 

 -'iHl-'il,')). — Methylguanidin, a constituent of meat extract, the author concludes 

 is formed by autolysis either after death or. more probably, during life and is 

 to be regarded as an oxidation product of creatin or creatinin. For earlier work 

 see E. S. R., 17, p. 683. 



Protein assimilation in the animal body, E. .\bderhalden and P. Rona 

 {ZtHchr. Phiixiol. Chriii.. J,l {19(16), \o. .',-6. pp. 397-.',03).—\\heu the body is 

 supplied with a lai-ge excess of protein the authors conclude, from their experi- 

 ments, that it has the power to select those which are best suited for the forma- 

 tion of body proteids. The experiments were made with dogs, and the balance 

 of income and outgo of nitrogen was determined. 



A law of growth reiterated, G. Lusk {Amer. Jour. Phi/siol.. 1.', (]D06), 

 \o. 3, Proc. .\)nrr. Physiol. .S'oc, 18 {1905), pp. XVII, XVIII).— The law which 

 the author formulates is that in the normal development of young of the 

 same age and si)ecies a definite percentage of the energy content of the food is 

 required for growth irrespective of the size of the individual. 



