f 6 ? 6 ] 
the -Society, and beg their Acceptance of this rough 
Sketch of the Do&or’s mod curious Difcoveries, which 
I have drawn by Memory, not having any of the 
Doiftor’s Papers by me, except fome Drawings, of 
which I herewith fend you Copies, [and are engraved, 
with fome Improvements, in the Tables annexed; fee 
Tab. I. Fig. a, 2, 3,4.3 
I fhall not here undertake to give a Defcription of 
all the Parts belonging to the Heart, fuppofing them 
already fufficiently known from the anatomical Wri- 
ters; but fhall only explain the furprifmg Simplicity 
of the Mufcular Structure of the HEART, as the 
ingenious Dr. Stuart hath demonftrated it from 
various Preparations of boiled Hearts ; viz. that the 
Heart is nothing elfe than a fingle Mufcle of nearly 
a femicircular Form , vuhofe Fibres are all parallel: 
For, fuppofc a rectangular Parallelogram A BCE ) , 
(fee Tab. I. Fig. 1.) confiding of Two Squares 
ABE F, and E EC E ; in each of which draw firft the 
Diagonals E B and C F j then fill the whole Paralle- 
logram, or both Squares, with Lines at equal Diftances, 
and parallel to the Diagonals : This done, at the Centre 
F, with the Radius FB , draw the Semicircle BEE). 
[and do the fame on the Back-fidc of the Paper; fo 
that every Line on the Back-fide may lie exa&ly 
under each corrcfponding Line on the Fore-fide, and 
that each Side may be as cxadtly alike, as if the Paper 
were tranfparcnt, and that the Lines might be lecn 
equally plain on cither Side:] Cut this Semicircle out 
of the Parallelogram, and cut out likewife a fmall 
lemicircuiar Piece at the Centre F; then roll up this 
femicircular Piece of Paper m a conical manner, fo 
that the Back-fidc of E) [or to 7 , in Fig. 2.] be folded 
