296 EXTERNAL GENERATIVE ORGANS, BY E. KLEIN. 



so that whilst the portion anterior to the urethra consists 

 exclusively of cortical substance, that is to say, chiefly of 

 muscular tissue, the posterior periphery of the prostate has 

 the cortex of the upper segment thicker than that of the 

 middle, and this again thicker than that of the lower portion. 

 It may also be perceived that the gland substance is most 

 strongly marked in the lower portion of the prostate lying 

 behind the urethra, whilst it is sparing in quantity in the parts 

 lying in front of the latter. The arrangement of the gland 

 substance is intimately connected with the muscular bands 

 penetrating it. In the lower segment of the prostate lying 

 behind the urethra, the muscular bands form a loose wide- 

 meshed structure, giving to this potion of the gland a spongy 

 character. In the middle segment they form a regular tunic, 

 investing the central uniformly dense hemispherical gland 

 mass, and from this tunic delicate fasciculi are given off that 

 dip inwaxds between the gland lobules of the central mass. 

 Lastly, over the upper segment the muscular bands are quite 

 unequally and irregularly distributed. Thus it comes to pass 

 that in the portions of the prostate lying behind the urethra 

 *ve have an upper more compact segment of the gland sub- 

 stance, a middle homogeneous segment, having a diameter in 

 the adult of 6*6 millimeters, and an inferior portion of more 

 spongy texture. 



In structure the gland presents the characters of the so- 

 called acinous glands, in which a gland duct bounded by a 

 structureless membrane divides, after pursuing a slightly 

 sinuous course, into two or more tubes provided with lateral 

 and terminal dilatations of various size and spherical or ovoid 

 shape. The wall, however, always remains structureless. 



In the central glandular mass the secondary ducts opening 

 into the principal excretory duct are beset with hemispherical 

 projections acini. In the lower segment only highly tortuous 

 ducts are present, which undergo frequent subdivision, exhibit 

 numerous dilatations of considerable size, and are singularly 

 looped and coiled at their extremities. 



The epithelium lining the acini and ducts is chiefly disposed 

 in a single layer of columnar form, the cells having a height 

 of 0'026 of a millimeter ; at certain points, however, as, for 



