PENIS. 



913 



they are firmly attached. The trabeculae are 

 most abundant in the middle line of the 

 organ, where they are extended in a vertical 

 direction from the middle line of the infe- 

 rior to the middle line of the superior wall, 

 forming a partial septum between the two 

 lateral halves of the corpus cavernosum. The 

 median partition is most complete posteriorly; 

 in front it is very deficient, and being com- 

 posed of parallel fibrous cords, between which 

 the cellular structure of the two sides of the 

 organ communicate, has given rise to the idea 

 from which it received its name of septum 

 pectinij'orme. The fibrous cords of the corpus 

 cavernosum serve, by means of their attachment 

 to every point of the interior of its fibrous 

 tunic, to equalise the pressure of the circula- 

 tion during erection, and prevent the undue 

 distention of its walls. The fibrous tunic is 

 variable in degree of thickness in different 

 parts of its extent; thus it is thin upon the 

 crura penis, and is thin also in the situation of 

 the inferior groove and at its extremity; in the 

 two latter situations it is pierced by several 

 vessels which communicate with those of the 

 corpus spongiosum and glans penis. 



The cellular structure of the corpus caver- 

 nosum is composed of a plexus of dilated 

 veins, which communicate with each other so 

 freely as to represent, when divided by a sec- 

 tion, a perfect network of cells separated from 

 each other by membranous parietes. The areae 

 of these venous cells are smallest near the cir- 

 cumference of the corpus cavernosum, where 

 they are separated by a greater thickness of 

 parietes, and greatest in the centre of each la- 

 teral half, where the intervening septa are thin 

 and membranous. The veins are lined in their 

 interior by a continuation of the common in- 

 ternal coat of the veins, and the interspaces be- 

 tween them are occupied by contractile fibrous 

 tissue. The contractile fibrous tissue is dis- 

 posed in parallel fibres separated to unequal 

 distances by common areolar tissue ; it is most 

 abundant in the thicker parietes of the veins of 

 the circumference of the corpus cavernosum, 

 and is diminished to two or three fibres in the 

 thinner walls of the central veins. The fibres 

 are straight in their direction, and arranged 

 transversely with regard to the cylinder of the 

 corpus cavernosum. Upon meeting the cy- 

 linder of a vein in their course they diverge 

 at an acute angle, and continue their straight 

 direction until again obstructed by another 

 vein, when they again separate without exhi- 

 biting any tendency to converge and enclose 

 the vein. At the point of divergence they are 

 crossed by other fibres at the same angle, but 

 coming in a different direction, so that the 

 parietes between each vein are formed by nu- 

 merous fibres of this tissue, crossing each other 

 at the angles of interstice between three or four 

 veins, but straight and parallel between every 

 two contiguous veins. The contractile fibrous 

 tissue is remarkably abundant in the horse, 

 where, from the redness of its hue, it resembles 

 muscular substance ; in man it is not abun- 

 dant but very distinct, and in some situations 

 I was enabled to detect it encircling the cylin- 



VOL.IIJ. 



ders of the veins, and forming as it were an 

 additional coat to those vessels. 



The contractile fibrous tissue of the corpus 

 cavernosum has been made the subject of con- 

 troversy between several of the physiologists 

 of Germany, on account of its resemblance to 

 muscular substance and the absence of other 

 attributes of muscular fibre. It is described 

 by Miiller in the 48th number of the Medici- 

 nische Zeitung des Vereins fur Ileilkunde in 

 Preussen, as a peculiar, red, fibrous substance, 

 and in the Archiv for 1835* he speaks of it as 

 a " substance having a fleshy muscular appear- 

 ance, of a pale red colour in the penis of the 

 horse, and also in the dog and man. It forms 

 an irregular network of columns (Balken) dis- 

 tantly resembling the network and trabecular 

 structure of the muscular columns of the 

 heart." His next inquiry was to determine the 

 nature of this substance. "To decide," he 

 says, " whether a reddish fibrous tissue be 

 muscular or otherwise, there are three modes, 

 the microscope, chemical re-agents, and expe- 

 riment on the living body. In vivisection of 

 the horse, dog, and ram, I saw no contraction 

 of this substance under the influence of the 

 galvanic current. The results of microscopic 

 investigation in the horse are unfavourable to 

 the opinion that it is muscular, for the fasci- 

 culi present no indication of the characteristic 

 transverse striae of muscular fibre, for although 

 the transverse striae be indistinct on the mus- 

 cular fasciculi of organic life, they nevertheless 

 exist. In stating the results of chemical in- 

 vestigation, I must remark that I speak solely 

 of this peculiar substance as examined in the 

 horse, and not of that of any other animal or 

 of man. To render these experiments accurate 

 and certain, it is necessary to remove from the 

 tissue every particle of tendinous fibre which 

 may pervade it, for this, as we shall perceive, 

 has a very different chemical composition. In 

 chemical characters, the substance under con- 

 sideration does not belong to those tissues which 

 afford gelatine by boiling, as is the case with 

 tendinous, cartilaginous, and cellular tissue; 

 for, after seven hours' boiling, I was unable to 

 extract from the pure tissue, separated from all 

 foreign substances, the slightest trace of gela- 

 tine. By boiling we obtain a substance preci- 

 pitable by infusion of galls, which does not 

 gelatinize, but gives oft a powerful odour of 

 osmazome. It agrees with muscular fibre and 

 fibrine in being precipitated from a solution in 

 acetic acid by ferro-cyanate of potash, and 

 differs in this respect from the class to which 

 cellular tissue, tendinous tissue, and elastic 

 tissue belong, for these are not invariably pre- 

 cipitable from a solution in acetic acid by ferro- 

 cyanate of potash. It would, however, be 

 incorrect to deduce the conclusion that this 

 tissue must therefore be muscular, for there 

 exists an entire class of substances whose solu- 

 tion in acetic acid is precipitable by ferro- 

 cyanate of potash, such as albumen, fibrine, 

 muscular tissue, and corneous tissue." 



* Page 28, in his report for the preceding year, 

 in reply to a misapprehension 011 ihe part of 

 Krause. 



3 N 



