the Author, is, that he has left the Progrefs of the Blood 
thro the Veins, and the Diaftoh of the Heart, abfolutely un- 
to uch'd, tho they are difficulties of a much greater Magni- 
tude, than this which he has attempted to account fo 
flightly for. For, in thefc he is excluded the benefit of 
Termjfion^ and has yet a greater refiftance to overcome 
witliout it. Omiffions of this kind are fo unufual with 
this Author, where-ever he knows himfelf to go upon 
fure grounds, that it is to me an Argument, that he doubt- 
ed the fufficience of his ^ercujjion^ and referv'd thefe im- 
portant Fh£mmena. for farther confideration , without 
plunging himfelf into fach an Abfurdity as to afcribe to 
FercHjJion any ^uoh Energy as to be able (fo broken as it re- 
turns to the Heart) by its re-aftion to force that Power, 
from whence only it was at firft derived. 
Dr Lower and Mr C^?2j?per deliver their Opinions of the 
Caufcofthe Dilatation of the Heart fo very fhort, and 
without any Arguments to fuppprt 'em, that by expofing 
em naked, they feem rather to difcourfe of it tranfiently, 
as men obliged by the nature of their Subjears to fay fome- 
thing of it^ than folicitous to give any full or fatisfadory 
Account, and therefore I (hall proceed no farther upon em 
here. 
But tho the Uyf othejls of BoreUm may in this cafe be 
found precarious or infufficient fa misfortune that has be- 
fallen him in divers other particulars) his Theory holds ftill 
good. At lead it ought to be allowed in juftice to his 
great Abilities and Exaftnefs, till fom^ body convifts him 
of fome material Error in his Calculations, which has not 
as yet been done by any body, that I know of. 
Suppofing then the Force of the Heart, and of the Mnf" 
cular Coat of the Arteries, as likewife of the refiftance, 
whjch they muft overcome, to be cojnputed with any de- 
gi]ee pf a<:quracy, there remains yet fuch a prodigious dif- 
pr^portipa ,to be accounted for, as requires fome more pow- 
erful Agent, than any yet alTiga'd, to make up the defici- 
ency. ' Dddddddd 2 What 
