CHEMJSTRY OF NERVOUS ACTIVITY 



955 



the limit beyond which recovery of the brain, and there fore successful 

 resuscitation of the animal, cannot be expected. 



Chemistry of Nervous Activity. Of this we are practically ignorant. 

 The percentage composition of the solids and the percentage of 

 water in the brains of three persons of different ages are ex- 

 hibited in the following table (W. Koch) : 



The next table shows the variations in the content of water, 

 solids, and protein in different parts of the nervous system (Halli- 

 burton) : 



The grey matter of the cerebrum in the adult contains 81 to 

 86 per cent, of water, the white matter 68 to 72 per cent., the 

 brain as a whole 81 per cent., the spinal cord 68 to 76 per cent., 

 and the peripheral nerves 57 to 64 per cent. In the foetus more 

 water is present (92 per cent, in the grey and 87 per cent, in the 

 white matter). 



The superior richness of the grey matter in proteins and the 

 preponderance of water in it are the chief chemical peculiarities 

 which distinguish it from the white matter. That it should have 

 * Calculated. f Calculated by difference. 



