U22 



VESICULA PROSTATICA. 



verumontanum, and possesses a flask-shaped 

 cavity of about one inch in depth. The open- 

 ing at the lower declivity of the verumon- 

 tanum is a fissure which has the shape of a 

 horse-shoe curved forwards, while a triangular 

 papilla, which arises from its posterior mar- 

 gin projects into it. In the Monodon the 

 hitter is farther separated by a linear fissure. 

 In a dolphin (JDclphlnus orca ?) which I ex- 

 amined, the anterior extremity of this papilla 

 was united with the opposite margin ; so that 

 the opening was divided into two fissures 

 converging superiorly. In the same way 

 Leydig observed it in Delphinus phoccsna ; 

 while in another individual of the same species 

 I have met with the condition previously de- 

 scribed. Possibly in younger individuals of the 

 Cetacea the Weberian organ has a yet greater 

 development. At least Eschricht, who was not 

 aware of the structure just described, states* 

 that, in a male embryo of the Plerobakena, 

 the inferior extremity of both vasa deferentia 

 was connected with a transverse fold, of which 

 the free margins exhibited the appearance of 

 an obliterated cord. From its situation this 

 would about correspond to the lateral horns 

 of an uterus. 



II. PHYSIOLOGY. We, now, proceed to 

 enquire what is the use of this structure, the 

 occurrence and variable forms of which we 

 have hitherto been treating of. It is a general 

 law that the physiological import of an organ 

 stands in a direct relation with its anatomical 

 development. If we regard the Weberian 

 organ in this point of view, we shall soon be 

 convinced, from its absence in many Mam- 

 malia, and from the varieties of its develop- 

 ment in particular individuals, that its in- 

 fluence upon life cannot be very important. 



When Morgagni first discovered the human 

 Weberian organ, he thought that it was con- 

 nected with the prostate. Its situation made 

 him think it possible that some tubes of the 

 prostate emptied themselves into it, and that 

 it was in a certain manner, like the gall- 

 bladder, a saccular dilatation of the excretory 

 duct of the prostate. But anatomical research 

 soon convinced him that his conjecture was 

 necessarily erroneous. A communication be- 

 tween the prostate and the Weberian organ 

 never exists, and is indeed rendered impossible 

 by an arrangement like that which obtains in 

 the horse, the goat, and the beaver. 



According to other views, the Weberian 

 organ has the function of a seminal receptacle. 

 Thus it has received the name of a vesicula 

 seminalis. But we know how prone the 

 earlier anatomists were to this designation, 

 and how they indicated in this manner all 

 those accessories of the male genitals of 

 Mammalia which opened near, or together 

 with, the ejaculatory ducts, without any closer 

 acquaintance with their structure and import. 

 More recent researches -f- have corrected us 

 on this point. They have shown us that the 



* Untersuchungen tiber die nordischen Wallthiere, 

 Liepzig, 1849, S. 102. 

 f Leydig, 1. c. 



dependent structures known as the dual se- 

 minal vesicles of the vasa deferentia almost 

 always possess a glandular texture, and never, 

 or only occasionally (as in man), contain 

 spermatozoa. It is true that the flask-shaped 

 seminal vesicles of the horse and ass are 

 genuine reservoirs of sperm, as we may 

 conclude from the fact, that the vasa defe- 

 rentia open into them, but as a rule exactly 

 the reverse relation obtains. 



But the same anatomical arrangement as 

 that of the vesicula seminalis in the horse 

 may be seen in the Weberian organ* of the 

 hare previously mentioned. On this ground 

 only one might conclude a similar functional 

 import. And the microscope really brings 

 proof that the contents of the Weberian organ 

 are, in this instance, sperm. 



But the connection of the excretory duct 

 and the Weberian organ is limited to the 

 hare and lagomys. In all the other Mammalia 

 the two structures open near to each other 

 without any communication. Now if, in spite 

 of this, the Weberian organ has the function 

 of a seminal receptacle, this can only happen 

 by the sperm, which has been previously 

 poured into the urethra, being discharged 

 through the lower aperture of the Weberian 

 organ into its interior. 



\Ve will not quite deny the possibility of 

 such an occurrence ; but the probability of it 

 seems but small. At any rate a contraction 

 of the muscular layer around the urethra 

 would be necessary thereto; but, without offer- 

 ing any new hypothesis, it would scarcely be 

 possible to perceive why the sperm should 

 thus be sent upwards rather than downwards. 

 The verumontanum alone would not be able 

 to prevent this. 



Such considerations would be silenced by 

 direct observation ; but hitherto no one has 

 ever met with real semen in the Weberian 

 organ, except in the hare. Morgagni states, 

 that on pressing the human vcsiculae seminales, 

 he has seen sperm exude from the prostatic 

 utricle. But the correctness of this state- 

 ment is rendered very doubtful by the fact, 

 that the examination was made at a time 

 when the accurate diagnosis of semen was not 

 yet understood. A fluid may certainly have 

 exuded from the Webe'ian organ, but that 

 it was sperm is very doubtful. It might easily 

 form the contents of the Weberian organ, 

 where, as is sometimes the case, this has an 

 abnormal communication with one or the 

 other vas deferens. 



I will not bring forward further arguments 

 against the import of the Weberian organ as 

 a seminal vesicle, such as its little capacity in 

 many instances, &c. They would only prove 

 that such a function is sometimes impossible. 



A third theory of the function of the vesi- 

 cula prostatica has been lately suggested 

 by Weber. According to this view it is a 

 kind of valvular ventricle, by which the urine 



* As has been also remarked by Leydig. H. Meckel, 

 on a priori grounds, wrongly denies this connection 

 in the hare. 



