( 4 ^^ ; 
ihould always be as its Quantity, but the Blood differing 
iikewile in thicknefs, the Dofes of Purging and Vomiting 
^ledicines muft be augmented on account of its thicknefs. 
1 his is perfedly well ' confirm’d by daily experience 5 
where we find, that People tick with a manifefi: thick- 
nefs of Blood, as in Dropfies, the Jaundice, 8cc. cake far 
greater Dofes than they did at any other time when they 
were not fick, or in that manner. 
By a further Difquifition into this matter, Wje find that 
the Dofes muft not only be greater where the thicknefs 
of Blood is greater ; but that they muft be encreas’d in a 
duplicate proportion of their Vifcidicy. This is evident' 
by the Tables in Ca^a. viz,. 9 ^ 8 ^ : 4 : 3 i 3, 
13 \gr, and therefore .altcrnAndo 9 : 4 : : 8 3 : 3 5, 19, 
Therefore the Dofes are as the Squares of the 
Conftitutions. So likewife 9 : 8 ^ : 16 : 14 3, 13 
and alternando 9 : 16 : : 8 3 : 14 5 , \ gr. h. e, the 
Dofes are as the Squares of the Conftitutions. 
The fime is true in any other Conftitution befides the 
mean : For Example, in the loweft and higheft 4:16:; 
213 I ^r: 853 f So that by this means we arc not only 
led diredly to a right ufeof thefe Medicines, and are able 
to find the true caufe why the ordinary Dofes produce fo 
very different effeds in different Conftitutions 3 but hke- 
'A Problem: wife, The §Harttity of Blood in any Perjhn being given 
together with the ordinary and extraordinary ef'eCb of a 
Dofe of a Purging Medicine^ the Change of that Perfons 
ConfUtHtion, and the Nature of that Change may be deter^ 
mind. 
ThisDoElrine It cannot but bc a great fatisfadion to the mind to find 
trite becaufe a Dodrine founded on a few fimple Experiences leading 
us into the caufe of many more that are ^very complexf, 
difficult, and obfcure 3 which is fufficient to prove its 
conformity to Nature. But ray prefent endeavour being 
to redify the common Pradice of thefe Medicines by this 
Dodrine, I fhall frame, by this Method, Tables of the 
Purging 
