THE ANTHK()P()L()(^Y OF THK 15RA1N. * 



Bv D. Keufoot Siiutk. M. 1). 



l>y '•aiitlu'opolojiy oftlu' brain" we niideistaiul several distinct, bnt 

 closely related, sciences, viz, tlie anatomy of the brain, its i)hysiology, 

 ])sycliology, ethnology, etc. 



In the short s])ace at my disposal it will 1k» impossible to do anything 

 more than brietly mention the more important facts bearing u})on this 

 interesting snbject. 



We will refer brietly, in the iirst ])lace, to tiic more salient featnres 

 of the anatomy of the brain. 



This complex viscns may be- looked upon as a hollow bag, with sev- 

 eral constrictions at ditterent places, whose wall is trilaminar, the inner- 

 most layer of which is named epeudyma. the middle one the nerve tissue, 

 and the external layer the pia mater. 



Tiie inner (ependyma) and outer (pia. mater) layers are (juite thin, and 

 may be said to maintain a uniform thickness; but the middle (nerve- 

 tissue) layer possesses very varying degrees of thickness at diflerent 

 points in the Avail of this hollow bag — the brain. 



The nerve tissuelayer may be very thick at some ])laces. and it may 

 be entirely absentiat other ]»oints. In this latter case the integrity of 

 the cavity oftlu'.brain is maintained by'the ependyma and ])ia mater 

 coming in contact, this.bilaminar portion of the brain wall taking the 

 general nameof velum. 



In oi'drr to give you. a necessary outline, idea of the anatomy mT th<' 

 brain, it will be best to refer rai)idly, but su(;cinctly, to the more salient 

 features of the embryology of the brain. At an early stage of ]>re- 

 natal groAvth the. brain consists of three i)ri ma ry vesicles; soon these 

 three, by additional growth and constrictions, be<*ome-./fyv' vesicles, all 

 In a series, one in, front of tlic-other (a^hollow bag with four constric- 

 tions and trilaminar wall). 



The technical name, for brain being encei)halon, these vesich's are 

 <lesignat«'d from Ix'fore backward, prosencephalon, thalam-encci)hal()n, 

 mes eiu;eyhalon, ep encei)halon, and met-encei)halon. 



The ])rosencephaIon, at tirst the smallest iind most anteriorly (pre- 

 axially) situated of all the .segments, is destined to grow out of all pro- 

 ])ortion to the other segments. It grows in all directions, ujiward, 



A .Saturday lecture deliviTcd in tlic Iccturc-li.ill of tlio U. S. National Munciiim, 

 uutter the auspices of the Autliroiilogica] .socief v of Washiniujtou. 



59.5 



