CHAPTER 9 



GROWTH OF CHEMICAL CONSTITUENTS 



1 . In the body as a whole. 2. In the nervous system. 



1. In the body as a whole. For the body as a whole Hatai 

 (MS '15) has made a determination of its composition in terms 

 of proteins, fat, organic extract and salts, at eight ages. The 

 results are given in table 77. 



TABLE 77. 

 Giving the chemical composition of albino rat. Hatai (MS '15) 



Age, days 



Body gms 



Water, per cent. . 



Solids, gms 



Percentages of 



Residue 



Fat 



Organic extr. 



Soluble salts. 



Fixed salts. . . 



294 



277.5 



65.3 



96.4 



44.5 

 16.5 



28.2 

 2.5 

 8.3 



The following paragraphs define the terms used in table 77. 



Residue. The residue is represented by the solids from which all the organic 

 substances soluble in both boiling alcohol and in water, as well as the salts have 

 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 present practically all salts present in the 

 osseous system. 



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