[885] 
I robferved alfo the brains of a flieep, and perceired 
ixi the Cortical parts, a very great multitude of extream 
thin blood Veffells, containing fome of thefubltance, 
which maketh the rednefs of the blood; whereby the 
jportical parts become of a brownifh colour. 
; \yhile I viewed the incomprehenfible number, of thefe 
fmail Veflells ; It was very delightfull to me, to contem- 
plate how every one of them, ^pread it felf intofeverall 
branches. 
There were alfo a great number of Globules not fo 
traafparent as others that were neer them, and that were 
in fize as | of a Globule, which maketh the rednefs in the 
blood : thefe I Judged to have been extrava fated, by the 
tearing of the VefTels afunder, and to have been fix of 
them compounded together, when the Veffells were wide 
enough to carry them j but when the Cavities were fo 
fmall, that they could not pafs thro* them, they then 
broke into lelTer parts, and loft their colour. 
For the better reprefenting the inconceivable thinw 
neis of the blood Veffells, I made the following Calcula- 
tions, m^. loo red Globules lyeing fide by fide, do not ' 
equall the Axe of a Sand ; let then a Million of them be ' 
equall to its folid content. There are blood Veffells in 
in the brain, which I judge ^ part of a blood Globule 
would be too big to pals thro* ; lo that the Diameter of 
the Veffell, is. to that of the Globule, as to 4, and if a 
couffe Sand be divided into 64. Millions of parts, i of the 
parts (if it be ftiff and rmplyable,j will not pafs thro' one 
of the fmalleft Veffells of the brain. 
To proceed, the Cortical p2,rt of the brain, was confti- 
tuted of fuch ^ elect and Glafs-Iike fubftance, asl havei 
above mentioned i only with this difference, that it had 
white ftreaks or lines, thinner then a hair of my head, 
which to the naked Eye were invifible. Thefe I judged 
to be occafioned, by a more then ordinary number, oi 
very tranfpareut great Globules layd together. Ihavd 
alfc 
