Now fuppofe H I to be aa artery,^ in which the 
blood moves upwards with equal fwiftnefs from 
H to I. — 
Out of H I arifes a venous Spring, delineated in 
K, L. 
The blood moving from K to F, joyns the other in 
F 'y and by this means part of the blood coming from 
the artery is thrown into the vein, as palEng from F 
to G 5 and to the beft of my obfervation, a quantity 
of blood, jaft equal to that carried from K F to G, 
moves from C E to F, and direfts its courfe upwards 
from F to L : fo that whatever arterious blood paifes 
thro F K and F G, an equal quantity of venous, blood 
pafles back thro C E and F L. 
Tho the delectable variety of the blood'^ motion 
was formerly apparent, yet this experiment pleas'd me 
beyond the others, by reafon that it afforded me a ve- 
ry clear perception of the ai^^ and 
befides this union of the blood veflefe was not formerly 
come to light. 
Twas feveral years that I had not feen the feed of 
a Cock 5 and now the ttpught being come into my 
:head, I view'd the feed of two feveral Cocks that were 
not yet arrived at their full growth 3 in order to trace, 
as much as poffible, the length and fingular narrow- 
nefs of the tails of the little animals in the male feed. 
But I could not cqmpafs ipy end, notwithftanding I 
try 'd 'em fometimes livings, apd fometimes dead. How- 
ever, I am certain that the leaft of the tails of thofe 
animals is more than 10000 times fmaller than one hair 
upon my hand 5 tho I cannot fay that I faw it di- 
ftindly- 
IV. .4 
