ORGANS OF THE BODY. 569 



wide-meshed capillary networks, which probably empty themselves like- 

 wise into the venous cavities of the part. 



Finally, the coats of the arteria profunda are supplied with a meshwork 

 of capillary vessels. These gather themselves together to form venous 

 twigs, also to be seen here, which empty themselves into a network of 

 venous spaces surrounding the artery. 



The so-called arterice helicince, brought into notice by /. Miiller, and 

 the subject of such frequent controversy, used to be supposed to terminate, 

 after many contortions and tendril-like convolutions, partly with blind sac- 

 cules in the cavernous spaces projecting into the latter. The appearances 

 which led to these conclusions were, however, artificial (Rouget, Langer), 

 produced in part by imperfect injection, partly by the constriction caused 

 by severed elastic trabecuke. 



The conveyance of the blood out 'of this system of lacunae is effected, 

 in the first place, in the dorsal portion of the organ, by short venous 

 passages, which spring from the deeper cortical network, and empty them- 

 selves into the dorsal vein of the penis (so-called vence emissarice). Again, 

 by the vence emissarice inferiores, which come- from the interior of the 

 cavernous system, and make their exit near the urethral furrow ; lastly, 

 by the vence profundce of the crura of the corpora cavernosa. 



In the spongy portion of the urethra we find a venous network inter- 

 nally around tl^e tube, consisting of long meshes connected with the 

 venous lacunae. In the bulb alone do we encounter a direct entrance of 

 arterial twigs into the lacunae : the transition in other localities takes 

 place through the medium of capillary networks, as seen, for instance, in 

 the mucous membrane of the urethra. 



In the spongy part of the glans, where the lacunar system is more or 

 less replaced by genuine venous vessels, the connection between arteries 

 and veins is everywhere effected through the medium of capillary inter- 

 lacements (Langer). 



The lymphatics of the male urethra, connected with those of the 

 bladder, are arranged in complicated networks, which, with longitudinally 

 arranged meshes, open directly into the lymphatic canals of the glans 

 penis. The latter are numerous, but thinner than those of the urethra 

 (Teichmann). They interlace in the uppermost layer of the skin in the 

 form of wide passages, seen in greatest numbers in the glans, and less 

 highly developed in the prepuce and other portions of the organ (Belajeff). 

 The larger trunks derived from these course along the dorsum of the penis, 

 and are received partly into the true pelvis, partly into the glands of the 

 groin. 



The nerves of the penis are derived partly from the cerebro-spinal 

 system (n. pudendus), partly from the sympathetic (plexus cavernosus). 

 The latter are stated to supply the cavernous tissue alone ; the first the 

 skin, and mucosa besides. The skin of the glans is peculiarly rich in 

 nerves. Many years ago Krause discovered terminal bulbs in this situa- 

 tion, and since then genital nerve-corpuscles (p. 327) have been also 

 observed. Tomsa mentions also a second and more simple mode of ter- 

 mination of the nerves of the glans. Pacinian corpuscles also were found 

 by Schweigger-Seidel behind the glans, in the neighbourhood of the dorsal 

 artery of the penis. 



In regard to the theory of erection of the penis, Koelliker endeavoured, 

 many years ago, to explain it as effected by a relaxation of the muscular 

 tissue of the corpora cavernosa under the influence of the nervous system. 



