DRY SUBSTANCE 



313 



been removed. Thus the residue as here defined represents practically all the 

 protein substances. 



Fat. Fat is represented by the substances soluble in boiling alcohol from 

 which the water soluble organic extractives and salts have been removed. 



Organic extractives. All water soluble substances from which the salts were 

 removed are called the organic extractives. 



Soluble salts. The salts here designated were obtained from all the extrac- 

 tives with both water and alcohol. 



Fixed salts. The solids from which fat, organic extractives and soluble salts 

 had been removed were incinerated and the ash thus obtained is here called the 

 fixed salts. Thus these fixed salts are practically all salts present in the 

 osseous system. 



Chart 56. Showing the growth of the dry substance (solids) as a percentage 

 of body weight, in the albino rat during the first third of its life span. Data 

 in table 166. To be compared with the corresponding graph in chart 50. 



Using the data for fat given in table 166, Moulton ('23) has 

 computed the percentages of water and of ash in Hatai's 

 series^ — on a fat free basis — including also observations by 

 Zuntz ('18) at birth, and Inaba ('11) at maturity. These values 

 are of course increased under such conditions. 



In a study of the effect of antenatal feeding on the weight 

 and composition of the young, Korenchevsky and Carr ('23a) 

 used the following diets : 



