446 Chemical Differentiation of the Brain 



CHART 3. Shows, in absolute weight, the amounts of proteins and of 

 lipoids in the brain of the albino rat at different ages. Based on Table 

 IV. 1, Proteins; , Phosphatides ; 3, Cerebrosides ; 4, Sulphatides; 5, Unde- 

 termined lipoids (Cholesterol). The organic extractives and inorganic 

 constituents are not included. For comparison the weights of the several 

 constituents in the spinal cord of the albino rat at 120 days are also shown; 

 the weight of the dry substance of the cord being taken as equal to that 

 of the 120-day brain. 



CHART 4. Shows, in the albino rat at different ages, the proportional 

 values in segments of a circle for the sulphur combinations (above the 

 equator) and for the phosphorus combinations (below the equator) ; with 

 a further grouping into colloids and non-colloids. Based -on Table IV. 

 Again for comparison the proportional values for the sulphur and the 

 phosphorus combinations in the spinal cord of the albino rat at 120 days 

 are also given. 



Sulphur combinations : 1, Proteins (protein sulphur) ; 4, Sulphatides (lip- 

 oid sulphur) ; 6, Neutral sulphur (proteic acids) ; 7, Inorganic sulphates. 



Phosphorus combinations : 1, Proteins (protein phosphorus) ;#, Phospha- 

 tides (lipoid phosphorus) ; 8, Organic and inorganic phosphates (water solu- 

 ble phosphorus). 



The colloids are represented by 1 and 4, of the sulphur combinations 

 and 1 and 2 of the phosphorus combinations. 



The non-colloids are represented by 6 and 7 of the sulphur combinations 

 and by 8 of the phosphorus combinations. 



