and Circulation of the 'Blood. 12 j 
fomething elde of a proper Height to fupport 
the Body of the Fifh ? it will lie in a very 
good Podtion for View, and the Circulation 
may be feen didindtly. 
Eels and Flounders live a long While out 
of Water, and are therefore mod; ufeful for 
this Service here at London ; but in the 
Country many Sorts of other fmall Fidies 
may be found much more trandparent. 
Mr. Leeuwenhoek informs us % that 
he daw, with great Admiration, in the lit* 
mod: Extremities of a very minute Fiill’s 
Tail, how the larger Arteries were there di¬ 
vided into the mod fine or evanefcent ones ; 
and that many of the dualled Veins, re¬ 
turning from the faid Extremities, met to¬ 
gether at lad in fome larger Vein. There 
appeared alfo in fome Veifels inch an Agi¬ 
tation of that Blood (which was protruded 
from the larger Arteries towards the eva¬ 
nefcent ones at the very Extremity of the 
Tail, and returned afterwards through many 
minute Veins into a large one) as hardly 
can be conceived. In the larger Arteries he 
could perceive a continual newProtfudon, or 
Acceleration of the Blood’s Gourde received 
from the Heart; but in the dual let* Arteries 
the Motion deemed equable without any 
* Arcan . Nat . Tom. IV. Epift, 65. 
Vol. I. K 
fuch 
