THE HUMAN PROSTATE GLAND 319 



Throughout its lower portion after the two branches join it is 

 surrounded by a thick layer of circularly arranged fibers enclosing 

 this other structure, which in some places seems to be a lumen 

 filled with degenerated epithelial cells and at others a space filled 

 with bundles of fibers undergoing degeneration. This structure 

 is about ten times as large as any of the blood vessels seen in the 

 section and does not bear any resemblance to tissue seen in this 

 or other series studied. 



There are five small tubules seen developing from the floor 

 of the bladder and extending down into the lower part of the tri- 

 gone. These are the subtrigonal glands. 



The circular fibers composing the sphincter at the vesical neck 

 are quite thick in this case and are intimately connected with 

 the muscle bundles of the bladder proper, while the trigonal 

 fibers although they are very few in number down here are super- 

 imposed on the fibers composing the sphincter. This arrange- 

 ment persists until the upper portion of the prostatic urethra is 

 reached where they become lost in the musculature of the urethral 

 wall. 



Just below the vesical sphincter there are found eleven evagina- 

 tions from the floor of the urethra which are lined with very fine 

 cylindrical epithelium and which in no case branch. These 

 tubules are recognized as the subcervical glands of Albarran and 

 their direction of growth seems to be upward toward the bladder 

 and in no instance do any of them extend deeply into the muscu- 

 lature of the urethra. 



In the region usually occupied by the middle lobe tubules of 

 the developing prostate gland, there is in this series an entire 

 absence of such tubules (fig. • 6) . Very careful study fails to 

 reveal any glandular tissue, except Albanian's tubules described 

 above, developing from the floor of the urethra between the en- 

 trance of the ejaculatory ducts and the cervix of the bladder. 

 Extending from each of the lateral lobes is seen a large branch 

 from the tubule nearest the middle line, which, if it should con- 

 tinue to grow and send out additional branches, would ultimately 

 form a bridge of tissue extending from one lateral lobe to the 



