146 



ERECTILE TISSUE. 



represents the plexiform arrangement of the 

 veins apparent on the surface of the glans, and 

 which empty themselves into the superficial 

 veins of the penis. 



Miiller having more recently investigated 

 the structure of the penis, has announced the 

 discovery of two sets of arteries in that organ, 

 differing from one another in their size, their 

 mode of termination, and their use ; the first 

 he calls nourishing twigs (rami nutritii), which 

 are distributed upon the walls of the veins and 

 throughout the spongy substance, differing in 

 no respect from the nutritive arteries of other 

 parts ; they anastomose with each other freely, 

 and end in the general capillary network. 



The second set of arteries he calls arteria heli- 

 ciiuE. In order to see these vessels, an injection 

 of size and vermilion should be thrown into a 

 separated penis through the arteria profunda : 

 when the injection has become cold, the 

 corpora cavernosa should be cut open longitu- 

 dinally, and that portion of the injection which 

 has escaped into the cells carefully washed out. 

 If the tissue of the corpora caveniosa be now 

 examined at its posterior third with a lens, it 

 will be seen that, in addition to the nutritious 

 arteries, there is another class of vessels of 

 different form, size, and distribution. These 

 branches are short, being about a line in length 

 and a fifth of a millimetre in diameter; they 

 are given off from the larger branches as well 

 as from the finest twigs of the artery. Although 

 fine, they are still easily recognised with the 

 naked eye ; most of them come off at a right 

 angle, and projecting into the cavities of the 

 spongy substance, either terminate abruptly or 

 swell out into a club-like process without again 

 subdividing. These vessels appear most obvious 

 and are most easily examined in the penis of 

 man, to which the following description refers. 

 These. twigs branch off from place to place, 

 sometimes alone, and sometimes in little 

 bundles of from three to ten in number; these, 

 as well as the former, project constantly into 

 the cells or venous cavities of the corpora 

 cavernosa penis. When the arteries thus form 

 a bundle, they arise by a common stem. 

 Sometimes such a vessel, whether it proceeds 

 from the artery as a single branch or as part of 

 a cluster, divides into two or three parallel 

 branches, which also either terminate abruptly, 

 or else swell out near their extremity. 



Almost all these arteries have this character, 

 that they are bent like a horn, so that the end 

 describes half a circle, or somewhat more. 

 When such a branch so divides itself, there 

 are formed doubly bent twigs inclined one to 

 the other. 



Many of these arteries enlarge towards their 

 end; this enlargement is gradual, and is greatest 

 at some little distance from the extremity, so 

 that the end is somewhat conical, terminating 

 immediately in a rounded point without giving 

 off any branches. The diameter of these arte- 

 rial twigs, in their middle, is from one-fifth to 

 one-sixth of a millimetre : those which branch 

 off from the trunk of the arteria profunda 

 penis are no larger than those which arise from 

 its finest twigs. It is by no means unusual to 



Fig. 98. 



observe the finest twigs of the arteria profunda 

 giving off branches of this kind which seem 

 much thicker than the twig from which they 

 arose. The annexed figure (fig. 98) (from 

 Miiller's Archiv.) repre- 

 sents a portion of the 

 arteria profunda penis of 

 man, with its arterise 

 helicinse somewhat mag- 

 nified. 



These remarkable arte- 

 ries have a great resem- 

 blance to the tendrils of 

 the vine, only that they 

 are so much shorter in 

 proportion to their thick- 

 ness, whence they have 

 received the name arterise 

 helicinae. Their termi- 

 nations may also be com- 

 pared to a crosier. By a 

 more minute examination 

 of these vessels either with the lens or with the 

 microscope, it will be seen that, although they 

 at all times project into the venous cavities of 

 the corpora cavernosa, yet they are not entirely 

 naked, but are covered with a delicate mem- 

 brane, which under the microscope appears 

 granular (Jig. 99). 



After a more forcible in- 



Fig. 99. 



jection this envelope is no 

 longer visible. When the 



arteries form a bundle, the 

 whole is covered by a slight 

 gauze-like membrane. 



With respect to this in- 

 vesting membrane, Profes- 

 sor Miiller appears to con- 

 sider it as performing an 

 important part in producing 

 the phenomena of erection. 

 These tendril-like arteries have neither on 

 their surface nor their extremities any openings 

 discoverable with the aid of the microscope ; 

 and when the blood, as it is probable, escapes 

 from them in large masses into the cells of the 

 corpora cavernosa during erection, it must 

 either traverse invisible openings, or pass 

 through small openings which become en- 

 larged by the dilatation of these arteries. If 

 the great number of the tendril-like branches 

 of the arteria profunda be compared with the 

 very fine nutritious twigs of the same vessel, 

 it is evident that when the former are filled 

 they must take up the greater part of the blood 

 of the arteria profunda; the diameter of the 

 profunda therefore not only includes its nu- 

 tritious twigs, but also the tendril-like branches, 

 which derive their blood from it, yet pro- 

 bably allow none to pass except during erec- 

 tion ; therefore the blood in the unerected state 

 only traverses the nutritive branches and ar- 

 rives at the commencement of the venous cells 

 in smaller quantities, while during erection it 

 probably passes in considerable quantity into 

 the cells through these tendril-like vessels. 



Professor Miiller, after pointing out the dif- 

 ference between the tendril-shaped vessels and 

 the looped vessels discovered by Weber in the 



