374 



S. HATAI 



TABLE 8 



Showing percentage oj nitrogen in the various nitrogenous organic extractives in 

 relation to the lipoid free solids (protein) in different parts oj the central 



nervous system 



central nervous system, when the water content is compared with 

 the brain weight from which the hpoids have been removed. 

 The percentage of water as thus determined shows a sHght 

 tendency to increase from the cerebellum to the spinal cord. 

 This may be due to the difficulty of extracting all the lipoids 

 from the substantia grisea — which substance in turn is relatively 

 more abundant in the upper members of the series. The value 

 for the water is nearly as high as that in the brain of the new born 

 rat. Thus the water-solids relation is not significantly altered 

 throughout life if the lipoids are excluded from consideration. 

 This interesting phenomenon has already been noted by Donald- 

 son ('16) in connection with the water content of the entire brain 

 of the albino rat during growth. Donaldson came to this con- 

 clusion by comparing the water content of the brain with the 

 myelin free solids. This constancy of water is highly interesting 

 since the water content appears to have intimate relation to, 

 or at least its abundance seems to indicate — the greater activity 

 of this organ — the nervous system — in which the water content 

 is high as compared with other organs 



DISCUSSION 



The nervous system is unique when compared \^ith other 

 organs or tissues in its ability to hold an enormous amount of 

 lipoids. From Koch's ('11) paper on "recent studies on hpoids" 

 which illustrates graphically quantitative relations between 



