[ 2 7 ° ] 
artery may (and does) often controul an Impetus of 
the blood, capable of burfting the internal (or liga- 
mentous, coat ; although this laft is by much the 
thickeft, and, feemingly, the ftrongeft. 
In regard to this diftention of the aorta ; as his 
Majefty had, for fome years, complained of frequent 
diftreftes and linkings about the region of the heart ; 
and as his pulfe was, of late years, obferved to fall 
very much upon bleeding; it is not doubted, but 
that this diftenfion of the aorta had been of long 
Handing, at lead: to fome degree ; and, as the pul- 
monary artery was thereby necelfarily comprelfed, 
and a refiftance, greater than natural, thereby oppofed 
to the blood’s dilcharge out of the right ventricle, it 
is reafonable to conclude, that a diftenfion and con- 
fequent weaknefs of the pulmonary artery and right 
ventricle, to fome degree, were nearly coeval with 
that of the aorta. But that the aorta had differed a 
more extraordinary and violent diftenfion, immedi- 
ately antecedent to the burftingof the ventricle, is evi- 
dent, from the recent fifture of the aorta, and the 
confequent extravafation of blood between its coats. 
Now, as this increafed and violent diftenfion of the 
aorta muft have been attended with a proportionate 
prefture upon the pulmonary artery, and, confe- 
quently, an increafed oppofition to the paftage of the 
blood out of the right ventricle; fo that diftenfion of 
the aorta muft be confidered, as the immediate caufe 
of the right ventricle’s being furcharged with blood, 
and confequently of its burfting. 
The immediate caule of this diftenfion of the aorta, 
as likewife of its being determined to that particular 
time, are naturally explicable, from his Majefty’s 
having 
5 
