PERITONEUM. 
point of the knife is properly lodged in the 
groove of the staff, and by the latter that it 
follows the groove fairly into the bladder. 
Some excellent instruments have been devised 
to prevent the occurrence of so serious an acci- 
dent, but to describe them here would be too 
wide a digression. 
The lithotomist is liable to commit other 
mistakes still in the same stage of the lateral 
operation. Tlis incisions may fall short of the 
bladder altogether, leaving the prostate insuffi- 
ciently divided; or he may, on the other hand, 
transfix the bladder by plunging his knife too 
deeply. The former error may lead to disap- 
pointment in extracting the stone, and to severe 
injury of the neighbouring parts in the attempt 
to do so; it admits, however, of correction if 
discovered in time, but the latter mistake must 
be irreparable. Occurrences such as_ these 
result from an imperfect knowledge of the 
depth of the perineum, and may be accounted 
for by the great variation in this respect which 
the region presents in different subjects. Du- 
puytren and Velpeau found the distance from 
the neck of the bladder to the integument of 
the perineum to vary in different cases to the 
extent of two inches and upwards, the disparity 
depending chiefly on the degree of obesity of 
the individual. 
The deep compartment of the anterior divi- 
sion of the perineum has claims upon the 
_attention of the practical surgeon independent 
of lithotomy. Matter sometimes forms within 
this space, and from the contiguity of the 
rectum on the one hand, and of the urinary 
organs on the other, such collections produce 
most distressing symptoms. The triangular 
ligament of the urethra prevents the abscess 
from gaining the surface directly, so that at 
length it either bursts into the rectum or makes 
its way gradually behind the base of the liga- 
ment. The finger introduced into the gut affords 
satisfactory information as to the nature of such 
cases, and free incisions through the perineum 
are followed by the most marked relief. 
Effusions of urine from accidental ruptures 
of the urethra occur less frequently behind the 
triangular ligament than in front of it, for in 
the former situation the canal is so thoroughly 
protected by its deep position that contusions 
inflicted upon the surface of the region but 
rarely affect it. False passages from the forci- 
ble introduction of instruments take place in 
general anterior to the triangular ligament; but 
when the urethra gives way behind a stricture 
in consequence of violent expulsive efforts of 
the bladder, the urine sometimes escapes into 
the deep compartment of the perineum, and 
destructive consequences are sure to ensue 
unless counteracted by timely treatment. 
Prostatic diseases are attended by a train of 
symptoms which depend upon the sympathies 
of neighbouring organs. When the gland sup- 
purates (not an uncommon consequence of 
acute inflammation), the matter usually dis- 
charges itself by the urethra, the tough capsule 
determining its route; but at times the abscess 
bursts into the rectum, or it may even point in 
935 
the perineum after passing behind the base of 
the triangular ligament. 
BIBLIOGRAPHY.—The following authorities may 
be consulted with advantage, in addition to the 
various systems of descriptive anatomy. Abraham 
Colles, A treatise on surgical anatomy, Dublin, 
1811. James Wilson, A description of two muscles 
surrounding the membranous portion of the ure- 
thra, Med.-Chir. Trans., vol. i, p. 175, London, 
1812. C. A. Key, A short treatise on the section 
of the prostate gland in lithotomy, London, 1824. 
Alf, A. L. M. Velpeau, Traité d’anatomie chirurgi- 
cale, ou anatomie des regions, Paris, 1826. Wil- 
liam Hargrave, A system of operative surgery, 
Dublin, 1831. Ph. Fred. Blandin, Traité d’anato- 
mie topographique ou anatomie des regions, Paris, 
1834, J. F. Malgaigne, Manuel de médecine ope- 
ratoire, Paris, 1834. G. J. Guthrie, On two new 
muscles of the membranous portion of the urethra, 
Lond. Med. and Surg. Journ., 1833. Robert Har- 
rison, The surgical anatomy of the arteries of the 
human body, Dublin. Thomas Morton, The surgi- 
cal anatomy of the perineum, London, 1838. Alf. 
A. L. M. Velpeau, Nouveaux elements de médecine 
opératoire, Paris, 1835. 
(Robert Mayne.) 
PERITONEUM.—The serous membrane 
of the abdomen, investing the inner surface of 
the abdominal walls and the outer surface of the 
abdominal viscera, and forming, by duplica- 
tion, sheets with both surfaces free, called 
omenta, mesenteries, suspensary ligaments, 
&e. 
The peritoneum of the male subject, in 
accordance with the rule of serous membranes, . 
is a shut sac: in the peritoneum of the female 
the single exception to this rule is met with: 
here the Fallopian tubes open into the perito- 
neal cavity, and their mucous surface is conti- 
nuous, through their fimbriated extremities, 
with the serous surface of the peritoneum. 
Another circumstance that renders the female 
peritoneum peculiar amongst serous mem-~- 
branes is, that it is necessarily ruptured in the 
occurrence of a normal process, namely, in 
the escape of an ovum. : 
The manner in which a single serous shut 
sac, by a kind of intus-susception, invests 
the external surface of viscera and the internal 
surface of the cavity in which they are con- 
tained, is admirably illustrated by the well- 
known comparison of a double night-cap. 
Where the cavity contains only a single viscus 
of a simple rounded form, as, for instance, 
the pericardium containing the heart, the com- 
parison is very apt. But when, as in the case 
of the abdomen, numerous viscera of irregular 
shape are contained in the cavity, the matter is 
much more complicated, and the resemblance, 
therefore, far less striking. Yet is the relation 
of the parietal part of the peritoneum to the 
visceral part, and of both to the abdominal vis- 
cera, essentially similar to that indicated in this 
well-known simile. The complexity of the 
peritoneal folds seems mainly to depend upon a 
strict adherence to such a simple relation, in 
the case of each of a great number of viscera, 
with their vessels, &c. contained in a single 
cavity. Each viscus, whatever its shape, whe- 
ther closely or loosely connected, must have its 
