f no ) 
In the Lateral 'Sinus’s, they arp feldom or nevernob- 
ferv’d ; becaufe in thofe, he thinks, they would have 
been more fubjeff to the fuperincumbent weight and 
preflare of the Brain, which would much have incom- 
moded their Office 3 but by their fituation in the Lon- 
gitudinal Sinus , there could no fuch iaconveniency hap- 
pen. 
From the aforefaid Glands innumerable fine Threads 
arife, and are only their Excretory Veflels, which are 
fpread all over the infide of the Pia Mater , being ac- 
companied and ftrengthned in their courfe by Fibres and 
other Blood Veflels. It is thefe Fibres which join' the 
Meninges to one another ; And if you take care that the 
Dura Mater be not hurt in taking off the upper part of 
the Scull, in dividing thefe Membranes, you may obferve 
Liquors of different colours ouze arid drop from them 
when cur. 
Our Author is not pofitive that thefe Excretory Duds 
penetrate into the Medullary Subftance of the Brain 3 
but affirms, that they creep along its inner Protube- 
rances and accidental Cavities. This Difcovery confirms 
what Bohn and fome others have faid about the Lym- 
phaticks of the Brainy but before our Induftrious Au- 
thor, none did ever fo much as pretend to fix their 
Origination, which he has traced from the Glands 
lodged in the Longitudinal Sinus , as above. 
The life he affig-ns to thefe Glands, is to feparate 
2nd flrain a particular kind of Humor from the Blood 3 
which, in his Opinion, may ferve to keep the Mem- 
branes and Surfaces of the Cavities and Protuberances 
of the Brain from growing too dry by their continued 
Motion. When this Humor becomes either deficient 
and wanting, or exuberant and in too great a quari- 
V*' ■ ' 
