or D, and cause an oedematous swelling
of the corresponding side of the face and the right arm. In the same way
an aneurism of the aorta, Q, by pressing upon the inferior vena cava, T,
may cause oedema of the lower limbs. Serum may accumulate in the
pericardium, owing to an obstruction of the cardiac veins, caused by
hypertrophy of the substance of the heart; and when from this cause the
pericardium becomes much distended with fluid, the pressure of this upon
the flaccid auricles and large venous trunks may give rise to general
anasarca, to hydrothorax or ascites, either separate or co-existing.
Tuberculous deposits in the lungs and scrofulous bronchial glands may
cause obstructive pressure on the pulmonary veins, followed by effusion
of either pus or serum into the pleural sac. [Footnote 2] An abscess or
other tumour of the liver may, by pressing on the vena portae, cause
serous effusion into the peritonaeal sac; or by pressure on the inferior
vena cava, which is connected with the posterior thick border of the
liver, may cause anasarca of the lower limbs. Matter accumulating
habitually in the sigmoid flexure of the colon may cause a hydrocele, or
a varicocele, by pressing on the spermatic veins of the left side. It is
quite true that these two last-named affections appear more frequently
on the left side than on the right; and it seems to me much more
rational to attribute them to the above-mentioned circumstance than to
the fact that the left spermatic veins open, at a disadvantageous right
angle, into the left renal vein.

[Footnote 1: The situation of this vessel, its close relation to the
pleura, the aorta, the large venous trunks, the vagus and phrenic
nerves, and the uncertainty as to its length, or as to whether or not a
thyroid or vertebral branch arises from it, are circumstances which
render the operation of tying the vessel in cases of aneurism very
doubtful as to a successful issue. The operation (so far as I know) has
hitherto failed. Anatomical relations, nearly similar to these, prevent,
in like manner, an easy access to the iliac arteries, and cause the
operator much anxiety as to the issue.]

[Footnote 2: The effusion of fluid into the pleural sac (from whatever
cause it may arise) sometimes takes place to a very remarkable extent. I
have had opportunities of examining patients, in whom the heart appeared
to be completely dislocated, from the left to the right side, owing to
the large collection of s