[ SS91 
As I aflerted above, that the particles of blood arc 
by a prefTure fo disjoyn*d, and united with the fluid 
matter in which they move, that the wIkjIg appeais as 
a fimple moifture 5 fo we may eafily imagine, that 
when a horfe (trains, and prefles his breaft in drawing 
a heavy load^ the globes ot blood are undone, and 
taken down in the midft of the veflels where the great- 
eft preflure comes, and as it were confounded or uni- 
ted with the fluid matter, call'd by Artifts Sertt/^, 
I have alfo bethought myfelf, that perhaps the un- 
done particles, when freed from the above-mention'd 
{training, may return to their former figure, juft as 
when a piece of the fat of an Ox or Sheep is laid in 
fuch a heat, that its particles, which come very near 
to the globes of the blood, are undone by the fire, and 
turn into a clear cryftalline liquor, vifible by a Magni- 
fying-Glafs : So Toon as the melting heat is gone from 
the fat, it prefently returns to its former globular parts^ 
and this will happen whenever it is cold, again, the ye 
melt it ten times or oftner. 
I have often fancy 'd, and been fully perfwaded, that 
no venous blood could become arterious, without be- 
ing firft in the heart : But forafmuch as the contrary 
lappeaKd to me in one of my Experiments, which I 
made purely for my own diverfion, I have a ftrong 
mind to give an account of the fame. 
Thele blood-veffels are defign d a little larger than 
they appeared to me .5 and in the middle of the fmall 
veflels a fiiiall fpace is left white, which other wife 
the particles of blood would alter, to the end that the 
motion of the blood may be the better perceived. 
Let us imagine AB in fig. 8. to be a vein, in which 
the blood f looked upon thro aMagnifying-Clafs) pafles 
with great celerity from B to A. 
Out of this vein run two little branches, v'z. C and 
D. which unite between E and F* 
Nov 
