J48 



PROSTATE GLAND. 



minent body, the base of which adhered to the 

 coats of the bladder. It was imbedded not 

 only between the vasa deferentia and the blad- 

 der, but also in some measure between the 

 lateral portions of the prostate gland and the 

 bladder, since they were in part spread over 

 it, so as to prevent its circumference from 

 being seen, and they adhered so closely as to 

 require dissection to remove them ; nor could 

 this be done beyond a certain extent, after 

 which the same substance was continued from 

 the one to the other. This proved to be a 

 lobe of the prostate gland ; its middle had a 

 rounded form, united to the gland at the base 

 next the bladder, but rendered a separate lobe 

 by two fissures on its opposite surface. Its 

 ducts passed directly through the coats of the 

 bladder on which it lay, and opened immedi- 

 ately behind the veru montanum." 



Fig. 102. 



A posterior view of the bladder and prostate, with third 

 lobe ; the vasa ejaculatoria and vesiculce are thrown 

 forwards. (From Sir E. Home.) 

 a, ureter ; b, bladder ; c, third lobe of prostate ; 



d, vas ejaculatorium, turned forwards ; e, vesicula 



seminalis ; /, vas deferens. 



It is well known that Hunter was aware of 

 the existence of this lobe as a natural consti- 

 tuent of the prostate, for he says, " A small 

 portion of it (the prostate) which lies behind 

 the very beginning of the urethra, swells for- 

 ward like a point, as it were, into the blad- 

 der ; acting like a valve to the mouth of the 

 urethra, which can be seen even when the 

 swelling is not considerable, by looking on the 

 mouth of the urethra, from the cavity of the 

 bladder in the dead body. It sometimes in- 

 creases so much, as to form a tumor project- 

 ing into the cavity of the bladder some 

 inches." Hunter has given an accurate draw- 



ing of the middle lobe of the prostate. In the 

 normal state it represents a simple elevation 

 of glandular structure beneath the uvula 

 vesicae, between the two lateral lobes at the 

 back part, and connected laterally with them ; 

 but it varies materially in size and consistence 

 in different subjects. 1 have no doubt that in 

 some cases it is wanting altogether, in others 

 it is of small size; and in many, where it is 

 well developed, it is as firm and consistent as 

 the other parts of the prostate. In one ex- 

 ample which I examined, it was much firmer 

 than the lateral lobes, and of a much lighter 

 colour ; indeed, so distinct did it appear that I 

 really doubted whether it belonged to the 

 prostate. I applied a microscopical test, and 

 found its ducts charged with similar concre- 

 tions to what have been so frequently found 

 in other parts of the gland ; this proved to me 

 that it was a part of the gland itself. The 

 best method of viewing the third lobe is to 

 make a vertical section from before backwards 

 through it, and to carry the incision directly 

 through the veru montanum, sinus pocularis, 

 urethra, and inferior part or isthmus of the 

 prostate, the divided third lobe is thus brought 

 into view, as well as the ejaculatory duct 

 of one side, passing between it and the lateral 

 lobe. The sinus pocularis runs beneath it (see 

 fig. 101). 



The urethra traverses the prostate from be- 

 hind forwards, and is completely surrounded 

 by it. Amussat doubted this fact, and thought 

 that only three fourths of the canal were en- 

 circled by the prostate, and that the remain- 

 ing fourth (the anterior) was covered by a 

 cellular or muscular medium, extending from 

 one lobe to the other. This is undoubtedly 

 incorrect as a general rule, for 1 have examined 

 with the microscope that portion of the gland 

 placed over the upper surface of the urethra, 

 and found it identical in structure with the 

 remainder of the organ. The urethra in pass- 

 ing through the prostate is dilated into a con- 

 siderable sinus, and presents in front a trian- 

 gular opening if a transverse section be made. 

 It is not exactly in the centre, being nearer 

 the anterior than the posterior surface ; it is 

 generally said to be about two lines distant 

 from the former, and four from the latter, and 

 seven from the lateral surface of the gland. It 

 varies frequently in this respect in a marked 

 degree. When the third lobe is small and 

 flat it is much nearer the posterior surface 

 than the anterior ; and this is the case where 

 the isthmus or medium of connection beneath, 

 is thin, a condition not very uncommon. 

 The prostatic portion of the urethra is about 

 fifteen lines in length, and is wider in the 

 middle than at either extremity ; it con- 

 tains within it the veru montanum or caput 

 gallinaginis, which runs along it, forming a 

 conical elevation, and dividing it into two 

 equal portions. 



Over the urethral surface of the third or 

 middle lobe of the prostate, the mucous 

 membrane is raised up so as in some subjects 

 to form a remarkable elevation, lying trans- 

 versely at the beginning of the urethra ; this 



