THE HUMAN PROSTATE GLAND 335 



they are somewhat larger. The position of the sub-cervical glands 

 of Albarran is even more strategic than that of the subtrigonal 

 group. Growing back directly within the sphincter it is easy to 

 see that a slight increase in size would form a very considerable 

 obstruction to the passage of urine from the bladder. 



4. The prostate gland begins to develop at the third month of 

 fetal life. The tubules which compose it make their first appear- 

 ance as solid epithelial outgrowths from five distinct parts of the 

 prostatic urethra. These solid masses of deeply staining cells 

 very soon become circularly arranged around lumen and branches 

 are found very early. The five foci from which groups of pros- 

 tatic tubules take their origin are located as follows: on the floor 

 of the urethra between the neck of the bladder and the openings 

 of the ejaculatory ducts and utriculus prostaticus, one in each 

 prostatic furrow and on the sides of the urethra, on the floor of 

 the urethra below the openings of the ejaculatory ducts and the 

 utricle, and on the ventral or anterior wall of the prostatic ure- 

 thra. The tubules originating from these five foci by their fur- 

 ther growth and the development of stroma around them become 

 the middle, right and left lateral, posterior, and anterior lobes 

 respectively. In early fetal life they are widely separated from 

 one another but in later stages the separation between the middle 

 and two lateral lobes is not very great. There is not an inter- 

 mingling of tubules in any of the specimens studied but in many 

 places in the new-born the tubules of the middle lobe are observed 

 side by side with those of the lateral lobes, there being no definite 

 capsule separating them. The separation of the posterior lobe 

 from the others is complete, as there is a rather dense layer of 

 fibrous tissue between it and the lateral lobes. The anterior 

 lobe is widely separated from the two lateral lobes. 



The first appearance of muscular fibers developing around the 

 tubules of the prostate is found at the sixteenth week at which 

 time a slight differentiation in staining properties is noticed. At 

 the twenty-second week the muscular layers are quite well devel- 

 oped and are particularly noted where some of the lateral lobe 

 tubules have extended away from the base of the prostate. The 

 musculature continues to become thicker and thicker until at 



