CHANGES IN THE COMPOSITION OF THE ENTIRE 



BODY OF THE ALBINO RAT DURING 



THE LIFE SPAN 



S. HATAI 

 The Wistar Institute of Anatomij and Biology 



ONE CHART 



The present investigation is intended to supplement a series 

 of anatomical data which have already been recorded on the 

 growth of the albino rat during its life span. As a first step in 

 the chemical investigation of the body as a whole, the changes 

 in the composition of the entire rat at different ages in respect 

 to its four main components; water, protein, fat and ash, have 

 been determined and the results are presented in the following 

 pages. 



In making the present analysis, the body was dried in an oven 

 at the temperature of 95°C. and the dried residue thus obtained 

 was subjected to a further analysis. Koch's (T3) investigation 

 shows that the material which has been dried by heat yields 

 slightly greater amounts of water soluble materials than the 

 fresh material which has been immediately placed in alcohol. 

 Consequently the value of the water extractives given in this 

 paper may be slightly high, nevertheless I feel that even if such 

 a difference occurs it is negligible when the degree of individual 

 variation is considered. 



I may state also that the extraction by ether and alcohol was 

 carried on until no more typical lipoid color was visible, even 

 after three hours continuous treatment. In isolating the water 

 soluble fraction from ether-alcohol extractives, I have followed 

 the technique devised by Koch and Mann ('09). 



The albino rats used for the present investigation were ob- 

 tained from the colony of rats kept at The Wistar Institute and 



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