ORGANS OF THE BODY. 565 



the lower end of the vas deferens is a fusiform dilatation, the " ampulla " 

 of Henle, from which a number of blind diverticula, leaving the main 

 tube, pass at very acute angles upwards into its walls. 



In this expanded portion of the canal the mucous membrane differs 

 from elsewhere : it is thicker and rugose, and presents a number of pits 

 and saccules. In the walls of the ampulla further vermiform glands pre- 

 sent themselves, filled with polyhedral cells, and containing molecules of 

 a yellow and brown pigment (Henle). The nerves of the vas deferens 

 possess* ganglion cells, and are medullated. Their mode of termination is 

 not yet known. 



The thin-walled vesiculce seminales have also a similar structure. They 

 are, in fact, little else than highly-developed diverticula of the same stamp as 

 the ampulla of the vas deferens, but branching. They are partly designed 

 as receptacles for the semen as it is secreted, and partly as secreting organs 

 themselves. Their walls are supplied with scattered bundles of smooth 

 muscular fibres. Within them we find a transparent fluid which coagulates 

 into a gelatinous substance on exposure to the air, becoming subsequently 

 liquid again. This is manifestly the same matter as the semen dis- 

 charged from the uretha (284). According to Gerlach, the rugose mucous 

 membrane with which they are lined contains numerous compound mucous 

 glands, which are stated by Henle to be of the tubular kind, and by Klein 

 to be only pits. Their structure is otherwise similar to that of the ampulla. 



The ejaculatory ducts correspond also in structure with the last-named 

 organs. 



Their calibre decreases greatly in their course through the prostate. 

 In the more dilated portions their mucous membrane presents similar 

 folds, tubular mucous glands, and yellow and brown pigment granules, as 

 the ampulla and vesiculse seminales. Within the prostate the muscular 

 layer of the ejaculatory duct gives place to cavernous tissue (Henle), and 

 the mucous membrane becomes thinner, smoother, and loses its glands. 



The prostate, the largest of all the organs connected with the male 

 generative organs, is an aggregation of glands belonging to the racemose 

 type, but presents, besides, many peculiarities. With Henle we may con- 

 sider it as divided into three portions, namely, the two sphincters of the 

 bladder, the internal formed of unstriped fibres, and the external with an 

 increasing number of striped elements ; and finally, the body of the gland 

 just mentioned. Besides a fibrous tunic with an admixture of muscle 

 elements, the prostate is enveloped in a tough yellowish membrane, con- 

 sisting chiefly of smooth muscular fibres. This latter sends off into the 

 interior of the glandular mass a number of processes forming a massive 

 framework, and making up a considerable portion of the whole organ. 

 The separate elements of the gland, in number varying from 15 to 20, 

 appear to be of the racemose kind. In them we find pear-shaped vesicles 

 of '12 54-0*2 3 mm. in diameter, lined with columnar epithelial cells. 

 The ducts of the gland are fine, surrounded by a muscular coat, and lined 

 with the same columnar epithelium : they empty themselves singly, in 

 the neighbourhood of the colliculus seminalis, into the urethra. 



The vascularity of the organ is considerable, its vesicle r s being enve- 

 loped in capillary networks. The lymphatics and mode of termination of 

 the nerves of the prostate which present ganglion cells are still unknown. 



The secretion of the prostate is probably allied to that of the vesiculse 

 seminales. In both we find an albuminous matter freely soluble in acetic 

 acid. 



