A HARD-WORKING DIET. 445 



Daily variations, even during health, in the amount 

 of fibrin (No. 2), fat (No. 4), and albumen (No. 9), are 

 often considerable, as the " storage " referred to on p. 

 35 1 fluctuates. The fact of such fluctuations is familiar. 

 For example, it can be observed with some exactness 

 by those who during the training of the University 

 crews watch the daily accounts of weights as given in 

 all the newspapers, or by those who at Turkish baths 

 keep records of their own fluctuations. 



The amount of phosphate of lime (No. 3), probably 

 nearly constant, depends mainly on the dimensions 

 (partly the density) of the bones, and heredity, feeding, 

 habits, and atmosphere, determine this during the first, 

 eighteen or twenty years of life. The amount of 

 fluoride of calcium (No. 12), and phosphate of mag- 

 nesia (No. 1 3) differ from the same cause of individual 

 structure. 



Such a table cannot of course be taken as an exact 

 account of the composition of all men of the size, 

 weight, and age mentioned. 



The chemical analysis is given first in compounds 

 and then as elements. 



COMPOUNDS. 



Ibs. ozs. grs. 



1. Water, which is found in every tissue and 



secretion, and amounts altogether to .. 109 o o 



2. Fibrin, and similar substances, forming the 



chief solid material of muscular flesh, and 



also occurring in blood .. .. .. 15 10 o 



3. Phosphate of Lime, in all tissues and liquids, but 



chiefly in the bones and teeth .. .. 8 12 o 



4. Fat, a mixture of three chemical compounds, 



distributed throughout the body .. .. 48 o 



Carried forward .. .. 137 14 o 



