282 



Preservation of Nerve Tissue 



C tmpirison of brains and cord* dried at 95C. with brain* arid cur da plnccd 

 directly in alcohol without 



In per cent of total solids. 



Distribution of sulphur in per cent of total S. 



Distribution of phosphorus in per cent of total P. 



' Obtained by difference. 



By drying there has been a destruction of the phosphatides involv- 

 ing a change in the distribution of phosphorus in per cent of total 

 phosphorus; that is, a considerable amount of lipoid phosphorus 

 is changed to water-soluble phosphorus. There was no change in 

 the sulphur distribution. It will be noticed that the phosphatides 

 of the cord are more resistant to heat than those of the brain, a 

 point of sufficient interest to justify repetition. 



We conclude, then, that the determination of water by drying at 

 95C. cannot safely be used, if it is desired to determine in the same 

 sample the relative proportions of the solid constituents; and that 

 the indirect method already described is far superior for this pur- 

 pose. 



