which is continuous in structure throughout, the ante-vesical or 'prostatic' mass nevertheless exhibits peculiar characters in the arrangement and combination of its component tissues; a special appellation may be therefore regarded as appropriate and necessary for anatomical purposes.

The view which regards the prostate as a separate organ is also supported by the fact that a glandular body similar to that in man is present as an accessory to other sexual organs throughout a large portion of the animal series, not only in the vertebrate class, but in the invertebrate also. And, lastly, there is the consideration which is supplied by the fact, that the prostate is subject to morbid changes which, as will be seen hereafter, are peculiar to it, and which do not occur in any adjacent or related structure.

These remarks are designed to explain that, although the prostate is not an independent organ like the liver, the kidney, or the pancreas, it has characteristics sufficiently distinctive to substantiate the claim here made.

The name of prostate,' as applied to the part under consideration, is supposed to have been originated by anatomists, from the fact of its standing before, or anterior to, the bladder or vesiculæ seminales, in the supine position of the subject; its name of 'gland' from the glandular structures which form a considerable part of its component tissues.

The prostate gland of the adult is commonly described as resembling a full-grown chestnut in size and form; sometimes it is compared in the last-named character to the ace of hearts, the small extremity being directed downwards and forwards, and the base upwards and backwards, in the erect position of the body.

When the bladder, prostate, and vesiculæ seminales, as well as the urethra for two or three inches of its course anterior to the prostate, are removed from the body and are fairly isolated from the neighbouring parts by dissection, the prostate appears as a mass having the form of a short truncated cone flattened between its pubic and rectal aspects, the base of which surrounds the neck of the bladder and projects somewhat below it, while its blunted apex ends at the fascial partition which stretches across the angular interval between the pubic bones, and is known as the posterior layer of the deep perineal fascia. The bladder should be slightly distended with tow, and the parts abovenamed should be properly secured to facilitate the dissection, with the posterior or rectal aspect upward, from which it is understood that the rectum itself has been carefully removed, without removing more of the fascia than is necessary in the operation.

First will be seen the vesiculæ seminales and vasa deferentia bound closely by a dense fascia to the posterior border of the prostate and base of the bladder adjacent, and requiring some careful dissection to isolate them fairly. Each vas deferens has a vesicula seminalis on its

outer side, and approaches obliquely the median line as it courses forward to the base of the prostate, and just before entering it joins the vesicular duct to form the common or ejaculatory duct. These two vessels, if carefully cleaned and traced, will be seen to perforate the mass in a deep central interlobular depression or notch, and to enter it in the middle line side by side. A layer of fascia, a portion of the rectovesical fascia, which forms an enveloping sheath for the gland, may be now dissected from its inferior surface and sides, where several venous sinuses will be encountered, especially along its lateral borders; those vessels being often large and generally filled with coagula, particularly in elderly subjects, sometimes also containing large phlebolithes. The proper capsule, which cannot be regarded as a mere offshoot from any adjacent fascia, but is a special envelope belonging to the prostate itself, although thin, is firm in texture, and defines clearly the form and limits of the prostate here. Proceeding with the dissection by turning upwards a little the peritoneum covering the bladder, and tracing the external layer or longitudinal muscles of that viscus, some bands of the paler and less superficial fibres will be found inserted into the base of the prostate above the point where the ejaculatory ducts enter. These being next divided, and the longitudinal layer turned aside from the base of the bladder to the right and left of the middle line, as well as the mutual interlacements of the different vesical coats permit, the inner or circular layer comes into view. These, which are very pale in colour, should be defined at the base and neck of the bladder, where they are chiefly aggregated, being thin and scattered above, since by tracing them forwards they will be found to be continuous with muscular fibres similarly arranged, and forming a considerable portion of the prostate itself. Next, in order to observe this continuity, the proper capsule must be partially removed, with the superficial and lateral portions of the prostate, which contain a large proportion of granular structure intermingled with interlacing muscular and fibrous tissues, to be described with the minute anatomy of the organ. Into this portion some fibrous prolongations of the capsule proceed, and minute vessels enter the prostatic substance with them. But in order to trace the circular fibres of the bladder through the prostate, a delicate dissection is necessary; and thus it is easy to demonstrate complete continuity of structure between the circular fibres of the bladder and the constituent fibres of the prostate, and that they are arranged around the tube of the urethra in the manner described. They may be traced along that canal, diminishing in volume in the anterior direction, as far as to the bulb of the urethra, where they stop, having extended over the whole of the membranous portion. In this latter situation they form only a layer from one-half to one-third of a line in thickness, although quite distinct. Lastly, if the circular fibres are removed with care, a longitudinal layer of

delicate pale muscular fibres is exposed, lying immediately outside the mucous membrane which forms that canal. These are the mus

cular fibres which surround the urethra throughout great part of its course, and which have been described in somewhat different terms by Hancock, Hogg, and Kölliker.

In order to present a clear view of the order in which the structures constituting the prostate are arranged, and particularly with regard to the urethra, which passes through it, they are here named in the reverse order to that already pursued, viz., from within outwards.

Firstly, the mucous membrane of the urethra.

Secondly, a delicate layer of longitudinally disposed pale or unstriped muscular fibres mingled with a good deal of connective tissue and some elastic fibres, this layer forming part of a system of longitudinal fibres underlying and surrounding in greater or less quantity the whole urethral canal.

Thirdly, a circularly disposed layer of pale or unstriped muscular fibres of considerable thickness posteriorly, where they become continuous with the circular fibres of the bladder, and becoming thinner as they approach the membranous portion, over which they proceed and then terminate. This layer contains also connective and elastic fibres like the preceding.

Fourthly, beyond this lies the greater part of the glandular structure properly so called, which intermingles with, and is supported by, a considerable portion of tissue, composed in part of pale muscular fibre, and in part of connective and fibrous tissues, which, interlacing together, constitute the rest of the organ. It is this composite structure which, disposed in masses chiefly in the lateral direction on either side, gives form and character to the organ.

Fifthly, the enveloping fibrous capsule.

To what precise portion of the mass lying anterior to the bladder and surrounding the urethra, shall we assign the limits of the prostate?

In front the posterior or deep layer of the perineal fascia may well be regarded as the boundary line. Behind we have no such limiting distinction, but we may proceed as follows. Taking a fresh specimen, in which the bladder and prostate have been carefully separated from the adjacent veins and fascia, and in which the vesiculæ seminales and ejaculatory ducts have been separated and traced into the interlobular notch, the basic extremities of the lateral lobes being defined, and division having been also made in front at the perineal fascia, we should lay open the bladder, and, with a pair of scissors, cut away the walls of the bladder closely round the neck or vesical orifice of the urethra. In doing so we shall divide the circular fibres freely, and some of the external longitudinal fibres, as well as the mucous membrane and submucous tissues around the internal meatus, particularly those forming the uvula or luette vésicale: the remaining portion may

then be accepted as a fair specimen of the prostate gland in an isolated condition.

It is this mass with which we have to deal in respect of external physical characters.

First, as to form. A slightly truncated cone, flattened antero-posteriorly, short, so that the diameter of the base exceeds by a fourth or fifth the measurement of the longitudinal axis, the base being notched or indented for the entry of ducts.

A drawing representing such a specimen in the supine position, and dissected in the manner described,

is presented in fig. 1.

FIG. 1.

A healthy prostate, from a man aged thirty

five years. It was dissected and accurately with its posterior or rectal surface downwards. The portion contiguous to the bladder is nearest to the eye; the internal meatus being seen

drawn while in the fresh state. The organ lies

above, and the ejaculatory ducts in their depres

Observing it more closely, the anterior surface appears generally convex. I have scarcely ever found any trace of a depression in the line of the long axis, said, in anatomical works, to exist and to correspond with the track of the urethra. The posterior or rectal surface is smooth and also rather convex, but here the course of the urethra is denoted by a shallow median depression, while the unyielding masses of the lateral lobes are seen, one on each side, and are still more readily recognised by pressure with the finger; two slight lines of depression are also seen converging at the basic part of this surface, which indicate the tracks of the ejaculatory ducts. At the base are seen the internal meatus of the urethra, and below it the interlobular notch and the funnel-shaped opening by which the ejaculatory ducts enter. It should be observed that the urethra perforates it at a point a little in advance of the base itself, approaching, in fact, to the upper surface, so that the portion of prostate below the urethra exceeds by about one-third or one-fourth the length of the portion which lies above. On each side of the base, the rounded posterior limit of a lateral lobe projects, a little backwards and outwards, leaving a notch between. The projection of a 'median portion,' or 'third lobe,' if present, is seen between the urethral opening and that for the two ejaculatory ducts beneath.

sion below.

Measurements.-The transverse diameter is almost always the greatest, exceeding the antero-posterior by a fifth or a sixth. These relations vary very much. Sometimes the organ has an appearance as if it had been compressed from before backwards. It is much less common to find the transverse measurement decreased.

In a mos of fly acts proses which I dissected and presented die Keñcu and Cherries Society, thin-re were healthy. Ther newstrament and verbs are famished in the following tables—

The point of extreme fckness when measured ranged between
But he measurement most commonly net with was about

1-4

2-4 ami 20

1-75 -53 and 95 T

The various statements regarding conformation, size, te, of the prostate given in this work are founded tedy these fissections, which were exhibited at the Medical and Chirurgical Society, Feb. 1. 1957, in usersden of a paper entitled Some Observations in the Anatomy ani Pathology of the Ainult Prostace,”