638 SPECIAL HISTOLOGY. 



and the bulbo-cavernosus muscles, which are formed of transversely 

 striated fibres, increase the rigidity of the anterior parts by the com- 

 pression of the root of the penis and dorsal veins ; but under no 

 circumstances can they, of themselves alone, contribute to the bringing 

 about of the erection. I am not aware that any more important func- 

 tion can be assigned to the helicine arteries ; this much being certain, 

 that the erection does not depend upon them, because they do not occur 

 in every part of the human penis, and are wanting in many animals. 



The investigation of the male sexual organs presents, generally 

 speaking, no great difficulties. The tubuli seminiferi are very readily 

 isolated, and when they are carefully unfolded some divisions are 

 always met with. In order to trace their entire course, they must be 

 injected according to the directions of Lauth or Cooper, which may be 

 found quoted in all Manuals of anatomy. Lauth places the testicle for 

 two or three hours in lukewarm water, then expresses the semen as 

 completely as possible from the epididymis, and immerses the gland 

 for 3-4 hours in a solution of carbonate of ammonia, or for 8-12 hours 

 in a saturated solution of carbonate of potassa, or a weak solution of 

 caustic potassa, which reagents partly dissolve the spermatic cells and 

 epitlielia ; the testis is then again compressed, laid in alkaline water, 

 and injected with quicksilver, at first under a weak and afterwards 

 under a strong pressure, a process requiring from 1J to 2 hours. So 

 soon as the quicksilver has penetrated into the vas deferens, the column 

 must be lowered to 5 inches, for otherwise the tubuli seminiferi, the 

 filling of which demands some hours more, burst. Cooper injected 

 from the vasa efferentia, into which he introduced a fine canula. For 

 microscopical investigation, Gerlach recommends a solution of gelatine, 

 with carmine or chromate of lead. The vas deferens is best studied in 

 transverse sections, after it has been hardened or dried, as are also the 

 prostatic glands ; whilst the muscles of the prostate and the corpora 

 cavernosa can be distinctly made out only in the recent state, or after 

 the application of nitric acid. The helicine arteries may be seen, even 

 in fresh preparations, close to the larger arterial trunks, but still better 

 after injection with fine materials. 



Literature. A. Cooper, " Obs. on the structure and diseases of the 

 testis," London, 1830, with twenty-four plates; E. A. Lauth, "Mem. 

 sur le testicule humain," in " Mem. de la socie'te' d'histoire naturelle de 

 Strasbourg," torn. I, 1833; C. Krause, "Verm. Beobachtungen" 

 (various observations), in Mull. "Arch." 1837, p. 20; E. H. Weber, 

 " De arteria/ spermatica deferente, de vesica prostatica et vesiculis semi- 

 nalibus," Progr., 1836, editum in Progr. collecta, II. 1851, p. 178; 

 " Zusatze zur Lehre vom Bau und den Verrichtungen der Geschlechtsor- 

 gane" (Contributions to the knowledge of the structure and functions of 



