INVESTIGATIONS IN HUMAN NUTRITION. 391 



more strongly does the organism lay claim to gelatin as a means of 

 protecting its living substance," and that when taken with abundant 

 carbohydrates glycocoU appears to be retained temporarily, if not 

 permanently, by the body. 



Folin*^ has continued his work with the products of proteid cleav- 

 age, especially with the metabolism of creatin and creatinin. lie 

 summarizes his conclusions as follows: 



There is no experimental evidence showing that creatin is the immediate precursor 

 of the creatinin appearing in the urine. Biologically, there seems to be a fundamental 

 difference between creatin and creatinin. * * * In the author's opinion it is 

 not yet clear whether creatin is a waste product or a food. 



F. G. Benedict and V. C. Myers ^ also studied the elimination 

 of creatin and creatinin with women in an insane asylum; they 

 conclude that the creatinin output is less in women than in men, 

 increases with age, and is probably proportional to body weight 

 rather than to the active mass of protoplasmic tissue. 



Lusk's '^ paper on the specific d3mamic effect of protein is of decided 

 interest. On theoretical grounds he believes — 



that the specitic dynamic effect of protein is due to cleavage which involves the 

 breaking down of the amid radical. If protein is resorbed rather than broken down, 

 such cleavage does not take place and no specific dynamic effect is noted. 



H. C. Sherman,*^ who has conducted a series of studies which con- 

 tribute much to the knowledge of the role of iron in food and in the 

 human body, investigated the amount of iron in the body, its occur- 

 rence in ordinary mixed diet, and in two special dietary studies, 

 besides conducting three metabolism experiments to determine the 

 income and outgo of nitrogen, iron, phosphorus, calcium, and mag- 

 nesium. It was found that the iron of the diet could be easily in- 

 creased without increase of protein by the use of vegetables, fruits, 

 and the coarser mill products of cereals, especially when accom- 

 panied by milk. 



In cooperation with J. E. Sinclair^ he has further studied the bal- 

 ance of acid-forming and base-forming elements in food, calculating 

 the amount of each element found to the corresponding number of 

 cubic centimeters of the normal solution of acid or base. 



By then adding together the results obtained it is easy to compare the totals, and 

 the result obtained shows the excess of acid-forming or of base-forming element,-^ in 

 terms of a familiar standard and in figures of convenient magnitude. 



a Brit. Med. Jour., 1906, No. 2399, p. 1787. Upsala Lakarefor. Forhandl., n. eer., 11 

 (190G), Sup. III. 



b Amer. Jour. Physiol., 18 (1907), No. 4, p. 377. 



fZentbl. Physiol., 21 (1907), No. 26, p. 861. 



d U. S. Dept. Agr., Oflice Expt. Stas. Hul. 185; Phm-. Soc. Expt. Biol, and Med., 4 

 (1906), 2, p. 21; Chem. Aba., 1 (1907), No. 5, p. 582. 



«Jour. Biol. Chem., 3 (1907), No. 4, p. 307. 



