2 7 



Chemical Differentiation of the Brain 



phosphatides, and cholesterol; in other words, an increase in sub- 

 stances which predominate in the fibres (medullated sheath) 

 during growth." 7 These same differences are to be found in all 



TABLE I. 



Relative proportion of the proximate constituents of the brain of the albino rat 

 at birth and when adult. 



In relative proportions of solids. 



Distribution of sulphur in per cent of total S. 



7 W. Koch and S. A. Mann: A Comparison of the Chemical Composition 

 of Three Human Brains at Different Ages, Journ. of Physiol, xxxvi, 

 pp. 1-3. (From the Proceedings of the Physiological Society, November 

 23, 1907). 



