146 Of the Nerves. 
of an Oxj and faw, with great Delight, that 
> minute hollow Veffels, of an unconceivable 
Finenefs, inveffed with their proper Mem¬ 
branes, and running out in Lengths parallel 
to one another, make up their Compofition. 
And though fome hundreds of thefe Veifels 
go to the Formation of the leaft Nerve that 
can poilibly be examined, he did not only 
difcern the Cavities of them, which he com¬ 
puted to be three Times lefs than their Dia¬ 
meters, but, in fome, perceived the Orifices 
as plainly as the Holes in a pricked Paper 
are to he feen when looked at againft the 
Sun. It requires, however, great Dexterity 
and Expedition to make this Examination 
with Succefs ; for after a thin Slice of the 
Spinal Marrow is placed before the Micro - 
ft cope , in lefs than a Minute’s Time it be¬ 
comes dry, and the whole Appearance va^ 
nifhes *. 
The fame ingenious Enquirer into Nature 
examined like wife the Brain of feveral Crea¬ 
tures, fbch as an- Indian Hen, a Sheep> an 
Ox, a Sparrow , &c. and could there diftin- 
guifh Multitudes of Veifels, fo extremely 
fmall, that if a •f* Globule of the Blood (a 
Million whereof exceed not a Grain oi 
Sand in Bignefs) were divided into five hun- 
-dred Parts, thofe Parts would be too large 
* Arc. Nat. Tom. Ilf. p. 3 IQ. 355. 440. 
f Ibid . Ton*.. I, Part. I. p. 30,. 
■ - ' to 
