BY B. C. GREY. 303 



Datajor molecular iveight determinations. 



No.l. 1-1668 grm. neutralised 33-9 cc. N/10 KOH. Mean mol. wt. 344-2. 



No.2. 1-3297 „ ,, 45-6 cc. N/10 KOH. „. ,, ,, 291-6. 



No.3. 0-5154 ,, „ 17-85CC N/10 KOH. ,, ,, ,, 288 7. 



No.4. 0-3595 ,, ,, 10-45 ce. N/10 KOH. ,, ,, „ 838-3. 



General conclusions. 



(1) The fatty acids of the human brain are more complex than 

 has previously been supposed. 



(2) The liquid portion contains fatty acid more unsaturated 

 than oleic acid, equivalent to not less than 22 Jo linoleic acid. 



(3) The solid portion contains, besides stearic and palmitic 

 acids, also a fatty acid of high molecular weight but low melting 

 point. It is not crystalline, and probably belongs to a different 

 group from stearic acid. 



In conclusion, I beg to express my thanks to Professor 

 Anderson Stuart, in whose laboratory this work was done; nnd 

 to Dr. H. G. Chapman, at whose suggestion it has been under- 

 taken. 



