C ) 
II. An Account of Animal Secretion^ the quantity of 
of Blood in the Human Body^ and Mufcular Motion, 
James Keill/ ,M. • 
« 
Author of cliefe Difcourfes prefixes a Preface, 
- wherein he fliows the heceffity of a right Know- 
ledge of the Principles oftrue Philofophy, and of the'A- 
nimal Oeconom^ in tlie Pracbice of .Phyfick ; where 
our Skill in curing Difeafes, wliofe Hiffones are known, 
js always ’ proportional to our Knowledge of the Ani- 
mal Oeconomy, which of it felf is atonfiderable part 
of Natural Philofophy. He does indeed blame the too 
common Method of Phllofophizing on Principles not 
dra\\^i from Nature,* but fuch as are the uncertain 
fidions of the Brain, whole real exiftence can never be 
, deduced from Experiments. This fort of Philofophy, 
he fays, is very prejudicial to Phyfick; Men being ge- 
nerally fond of their own Produftions, have hot hack 
to mould new Difeafes to anfwer their Hypothefis 3 fo 
. that mod: of the late Hiftories of Difeafes are only Phi- 
lofophical Romances ; but notwithhanding this, Natu- 
ral Philofophy^ and the Hiffory of Difeafes ‘muff go 
Hand in Hand In improving the Art of Curing: And 
he affirms, that there is no Man that pradliles, but 
who does it on fome Knowledge of the Animal Oeco- 
nomy, orfome Notions of his own, which are more or 
lefs clear, according to his Skill in Natural Philofophy. 
He proves likewife from Hyfocrates and Gden^ that the 
'•Principle of AttraTion of the fmall Particles of Matter 
to one another, was known to the Ancients j the Phi- 
lofophy of Hjpocrates being built on a certain propenfion 
which fome things have to one another, whereby they 
attrad, retain, and alter each other. 
In 
