954 MALE ORGANS OF GENERATION, 



size ; the third, or middle lobe, is a smaller rounded or triangular mass, 

 intimately connected with the other two, and fitted in between them on the 

 under side, lying immediately beneath the neck of the bladder and the 

 adjacent part of the urethra. This third lobe is exposed by turning down 

 the seminal vesicles and ducts, between which and the cervix vesicse it is 

 placed ; being in fact the part of the gland contained between and behind 

 the grooves or fissures by which the ejaculatory ducts reach the urethra. 

 The separation between these lobes, which is little marked in the natural 

 state, becomes often much more apparent in disease. 



Structure. The prostate is enclosed in a dense fibrous coat, which is 

 continuous with the recto-vesical fascia, and with the posterior layer of 

 the triangular ligament, and is rather difficult to tear or cut. Adams 

 describes the fibrous capsule as divisible into two layers, between which 

 the prostatic plexus of veins is enclosed. The prostate is a highly muscular 

 organ ; its external coat contains numerous plain fibres ; within the proper 

 glandular structure, which lies somewhat superficially, there is a strong 

 layer of circular fibres continuous posteriorly with the sphincter vesicse. 

 Ellis finds that these muscular fibres not only join behind with the circular 

 fibres of the bladder, but are continuous in front with the thin layer hereafter 

 described around the membranous part of the urethra (p. 962). According 

 to Pettigrew, the muscular fibres of the prostate are the lower parts of 

 figure-8 loops, which spread superiorly on the bladder. The substance 

 of the gland is spongy and more yielding ; its colour is reddish grey, or 

 sometimes of a brownish hue. It consists of numerous small follicles or 

 terminal vesicles opening into elongated canals, which unite into a smaller 

 number of excretory ducts. These appear either as pores or as whitish 

 streaks, according to the way in which they are exposed in a section. The 

 epithelium in the vehicular terminations is thin and squamous, whilst in the 

 canals it is columnar. The capillary blood-vessels spread out as in other 

 similar glands on the ducts and clusters of vesicles, and the different glan- 

 dular elements are united by areolar tissue, and supported by processes of 

 the deep layer of the fibrous capsule (Adams). The ducts open by from 

 twelve to twenty or more orifices upon the floor of the urethra, chiefly in 

 the hollow on each side of the verumontanum (p. 963). (Adams, Cyclop, 

 of Anat., vol. iv., p. 147 ; Ellis and Pettigrew, referred to at p. 951.) 



Vessels and Nerves. The prostate is supplied by branches of the vesical, 

 hsemorrhoidal, and pudic arteries. Its veins form a plexus round the sides 

 and base of the gland, which is highly developed in old subjects. These 

 veins communicate in front with the dorsal vein of the penis, and behind 

 with branches of the internal iliac vein. According to Adams, the lym- 

 phatics, like the veins, are seen ramifying between the two layers of the 

 fibrous capsule. The nerves are derived from the hypogastric plexus. 



Prostatic fluid. This is mixed with the seminal fluid during emission; as obtained 

 from the human prostate soon after death, it has a milky aspect, which is ascribed 

 by Adams to the admixture of a large number of epithelial cells, and he thinks it pro- 

 bable that, as discharged during life, it is more transparent. According to the same 

 observer, the prostatic fluid has an acid reaction, and presents, under the microscope, 

 numerous molecules, epithelial particles both squamous and columnar, and granular 

 nuclei about -^ m inch in diameter. As age advances, this gland is disposed to become 

 enlarged; and its ducts often contain small round concretions of laminated appear- 

 ance, and varying from a small size up to that of a millet-seed; they sometimes con- 

 tain carbonate of lime, but are principally composed of animal matter, which in some 

 of them appears to be entirely amylaceous, in others albuminous, and more frequently 

 is of a mixed character. (Virchow's Cellular Pathology, by Chance, p. 369.) 



