251 
PATHOLOGY. 
"paffive aneurifm,” is diftinguifhed by the following 
anatomical characters—enlargement of the cavities of 
the ventricles, the fides becoming thinner. Thefe marks 
are commonly attended with a foftening of their muf- 
cular fubftance, a colour fometimes bluer than natural, 
at other times more pale, inclining to yellow. The fides 
are fometimes faftened to fuch a degree, efpecially thofe 
of the left ventricle, as to yield to the preffure of the 
fingers; and they become fo thin as not to exceed (in 
the left ventricle) two lines in the thickeft part, and at 
the extremity fcarcely half a line. The extremity of the 
right ventricle is fometimes thinner ftill, appearing to 
confift only of a little fat and a (trip of the internal or 
ferous membrane of the pericardium which covers the 
heart. The flefhy columns, particularly thofe of the 
left ventricle, are manifeftly more diftant from each other 
th.an in the natural Urate. The interventricular partition 
lofes lefs of its thicknefs and confidence from the effeft 
of the dilatation than the reft of the parietes of the heart. 
The dilatation may affeCt one ventricle only ; but it is 
more common to find them both affeCied at the fame 
rime; which is the more remarkable, as in hypertrophy 
the contrary takes place. When one ventricle only is 
affeCled, its extremity reaches lower than the other, 
but this difproportion is not fo great as in hypertrophy; 
and the enlargement of the dilated cavity appears rather 
to be in its diameter than longitudinally; infomuch that 
a heart which has both its ventricles dilated, becomes 
rounded, and very near as large at the apex as at the 
bafe ; and in Ihape it will appear like a pouch, rather 
than of the conic form which is natural to it. 
As to the caufe of dilatation of the heart, fome differ¬ 
ence of opinion is found amongft the belt authors. 
Corvifart conceived, that, when the fyftem was in a ftate 
of plethora, or the heart, from other caufes, kept much 
in a ftate of congeftion, it had a tendency to dilate in 
one or more of its cavities. With the dilatation of the 
auricles he almoft invariably found a correfponding iti- 
creafed tenuity of the parietes. In the right ventricle 
too, the walls generally became thinner as its capacity 
increafed ; but in the left ventricle, the contrary. He 
confidered the caufe to be preffure on the parietes from 
the fulnefs of the cavities, which in their dilatation be¬ 
came attenuated or thickened, not from fuperadded dif- 
eafe, but from the inherent and original diverfity cf 
ftruCture. He conceived the fymptoms would be found 
to correfpond with this explanation : That in aClive 
aneurifm the powers of the heart would be found to be 
increafed; its concufiion on the cheft great, and the 
pulfe proportionably ftrong. 
M. Roftan arrived, after a very laborious inveftigation 
cf the fubjeCV, at fomewhat different concluiions. He 
convinced himfelf that dilatations, with increafed thick- 
iiefs, were not to be afcribed fimply to the effeCt of in¬ 
ternal impulfe, modified by the original charadler of the 
cavity, but that invariably fome extrinfic caufes could be 
found; that the current of the circulation was oppol'ed 
either at the valves, or at fome remoter diftance ; that 
the heart endeavoured to overcome this refiftance; that 
in this effort its parietes were often increafed in thick¬ 
nefs, and its powers in ftrength. Patient examination 
declared the obftru&ion fometimes to exift at a diftance 
from the centre of circulation, which had not previoufly 
been contemplated, deep in the fubftance of the lungs, 
or far in the courfe of the aoita. He conceived the dif- 
eafe to occur more frequently in the right ventricle than 
M. Corvifart had done. Claiming then the merit of af- 
ferting for this caufe the confequence it bore, one which 
feemed fo fatisfa&orily to account for the appearances, 
he upon the whole agreed with his fellow-labourer in the 
fame field, that where there was increafed thicknefs there 
was increafed power. He very clearly, however, demon- 
ftrated how all this might exift without its manifefting 
itfelf by thofe fymptoms of increafed ftrength and power 
on which M. Corvifart had dwelt. The heart was mak- 
Vol. XIX. No. 1301. 
ing its effort to overcome fome refiftance, and the full ef¬ 
fect of its impulfe could be felt only to the point of ob- 
ftru&ion. Hence you could no longer depend on mere 
ftrength of pulfe as a diftinguilhed fign of dilatation with 
increafed thicknefs of parietes. Imagining that he had 
thus afcertained, more fatisfaCtorily than had previoufly 
been done, the key-ftone on which much learned 
lore had been built, the caufe of that clafs of difeafe ge¬ 
nerally denominated attive dilatation, M. Roftan’s invef- 
tigations difclofed another truth. The caufe of obftruc- 
tion fometimes aCted fo long, and the thickening in¬ 
creafed to fuch an extent, that it encroached upon the 
capacity of the cavity. Seeing how this could be readily 
explained, that it was but a further effefl of the fame 
caufe, he very naturally allowed it to remain in the clafs 
to which it was moft allied. In feveral cafes he found 
the cavity fo fmall, that it would hardly contain a wal¬ 
nut. 
But the conclufions both of Corvifart and Roftan betray 
too ready a tendency to draw general conclufions; for 
it now feems pretty clearly afcertained, that the difeafe 
which M. Roftan attributes uniformly to fome obltruc- 
tion in the courfe of the circulation, may fometimes arife 
independently of this or any other very apparent caufe. 
M. Laennec properly confiders, that it is occafionally an 
idiopathic affection of the heart, though not of frequent 
occurrence. 
The figns of a dilatation of the left ventricle, according 
to M. Corvifart, are—“ pulfe foft and feeble ; palpita¬ 
tions weak, dull, finking; the hand feems to feel a foft 
fubftance which raifes the ribs, not ftriking them brifk- 
ly ; and preffure feems to render the beats more feeble. 
Very little found proceeds from the region of the heart.” 
But the only certain evidence of a dilatation of the left 
ventricle, according to Laennec, is that produced by the 
ftethofcope; namely, the ruftling roaring found of the 
contractions of the heart heard between the cartilages of 
the fifth and feventh ribs of the fternum. The loudnefs 
of the found, an 4 d its extent, (how the extent of the dila¬ 
tation. Thus, if the found of the contraction of the 
ventricle is as loud as that of the contraction of the au¬ 
ricle, and the beatings of the heart are at the fame time 
evident on the right fide of the back, the dilatation is 
very confiderable. 
Dilatation of the right ventricle, according to M. Cor¬ 
vifart, is accompanied with nearly the fame fymptoms, as 
to the ftate of the pulfe and the beating of the heart, 
which however are rather more evident, of courfe, on the 
right fide, that is, near the fternum and towards the epi- 
gaftrium, than in the region of the heart properly fo 
called. He, however, places not much reliance on this 
fymptom, nor on that of Lnncifi, namely, the fwelling 
or puffing-up of the external jugular veins. The fymp¬ 
toms he thinks moft to be depended upon are—greater 
difficulty of breathing than in the affeCtions of the left 
ventricle; a more decided ferous diathefis; more fre¬ 
quent hemoptyfis; a more dark lividity in the counte¬ 
nance, fometimes even the darkeft blue. 
“Thefe obfervations,” fays Laennec, “are in general 
correCl; but I cannot entirely concur with my celebrat¬ 
ed mafter (Corvifart) as to the importance of two of 
thefe fymptoms—the fwelling of the jugulars, and the 
extent of the abfence of found in the region of the heart. 
An habitual puffing-up of the external jugular veins, but 
without fenfible pulfations, lias appeared to me the moft 
conftant (doubtful) fymptom of dilatation of the right 
cavities of the heart. As to the abfence of found, I have 
often found the right cavities much dilated in cafes where 
the breaft emitted a confiderable found in the precordial 
region and under the fternum ; and in general it has ap¬ 
peared to me, that the difeafe of the heart which produced 
moft frequently the fuppreffion of found was not this, 
but “ hypertrophy combined with dilatation,” of which 
we fliall prefently fpeak. As to M. Corvifart’s remark 
of the more intenfe lividity of the countenance in dila- 
3 T tatioa 
