Royal Society. 383 
ne Manner of Concoction 5 l?y 2)r. Clopton Havers. Phil. 
Tranl^ N° ^54. p. 233. 
THE fentiments of phyficians, about the manner how the 
digeftion of the alinnent is performed, have been various, 
and the hypothefes, by which they have endeavoured to explain 
it, very different 5 fome have been of opinion, that it is a Jcind of 
elixation, and that the grofler and more Iblid parts being, as it 
were, boiled in the fluid by the heat of the flomach, and the 
parts adjacent thereto, as the liver, fpleen, and Omentum^ are by 
a long and continued elixation firft rendred more tender, and 
then colliquated and diflolved into minuter particles, i'o as to mix 
more equally with the fluid, and therewith to make one pulp 
or chylous mafs3 and tho' Hi-ppocrates does not plainly call it 
an elixation, yet he leems to attribute the concodion of the 
food to the heat of the flomach, as its great caufe: Others 
have luppofed it to be performed by attrition 5 as if the flo- 
mach, by thofc repeated motions, which are the necefTary 
effecls of refpiration, when it is diftended by the aliment, did 
both rub or grind off fbme minuter particles from the grofler 
parts, and by continually agitating the mafs of food, make thofe 
parts of it, which are not contiguous to the flomach, ftrike one 
againfl another, and break one or the other into pieces, till they 
are all attenuated 5 as for bread and fuch things as are made of 
flour, that may be foftened and diflblved v^ith any common li- 
quid, tho' that agitation of the flomach, which moves them in 
refpiration, might feem fufficient to break and diffolve them 3 yet 
this cannot be thought fufficient to break and digefl fleih-mear, 
fruits, or any other thing that will not be fbftned and difiblved in 
water, or fome fuch liquid; but altho' this motion of the ali- 
ment, caufed by refpiration, does not actually digeft it, yet it has 
a great and necefTary ufe in conco6lion, and makes all the grofler 
parts as they are attenuated, mix equally with the fluid parts : 
Others think that the bilious juice, others again, that the ipirits 
are chiefly concerned in this affair ; Galen makes it the eftecl: not 
of one, but of leveral cauics^ as the pituitous juice in the flo- 
mach, the bile, ^c. Some there are that will have the food dif^ 
folved by amenftruum, Ibpplied from the glands of the flomach, 
or fome other way ; but thele differ in their notions of the nature 
of the menftruum; for there are fome that fuppofe it to be an 
acid, which corrodes the grofler parts of the food, and diffolves 
them in the fame manner; as vinegar, fpirit of vitriol, ^c. which 
£ven diffolve fuch a fblid body as iron 3 and tho' it cannot be de- 
nied 
