Hdemajlatlcs. 163 
by the great Compreflure of the Abdomen on 
its Veins, but alfo when thofe Veins (which 
are the great Store-rooms of both the necei^ 
fary and too redundant Fluids) are too pletho- 
ric, in proportion to the Degrees of which, 
the free Courfe of the arterial Blood will be 
rebated ; And the Heart being in this cafe like, 
a Water-Mill that is furcharged with a Flood 
both before and behind, its Force niufi: need^ 
abate and grow languid ; in which cafe Eva- 
cuation by bleeding, is well known to reftore 
it to its natural Vigour. 
17. When the Courfe of the Blood is re- 
tarded by feme Defeft in one part, it occafi- 
ons thereby a greater Flow of it on other 
Parts : Thus feme of thofe that have a Limb 
cut off, have been obferved to be fubjefit to 
Haemorrhages ; and for the fame Reafon a feir- 
rhous Liver and Spleen will caufe a vomiting 
of Blood, hence alfo when the Spleen is cut 
out, the Liver increafes. 
18. As the Vigour of the Blood in the Ar- 
teries and Veins is thus greatly increafed by the 
increafed Preflure on the Blood-veflcls in the 
Abdomen ; fo is its Vigour much rebated when 
on the contrary the Blood-veffels of the Ab^ 
domen are too little compreffed 5 thus when in 
Mi a Dropfy 
