554 OF SECRETION. 



in the temporary structures ; at first their efferent ducts open into those of the Wolffian 

 bodies, but they are subsequently separated by the formation of a partition, like that 

 which separates the rectum from the cloaca. In the Human embryo, the rudiments of the 

 sexual organs, whether testes or ovaria, first present themselves soon after the kidneys 

 make their appearance, that is, towards the end of the seventh week. They are at first 

 much prolonged, and seem to consist of a kind of soft, homogeneous blastema, in which 

 the tubular structure subsequently develops itself. The Ovary at that period has the 

 same aspect and texture ; but its subsequent course of development is different. The 

 Testis gradually assumes its permanent form; the epididymis appears in the tenth week; 

 and the gubernaculurn, (a membranous process from the filamentous tissue of the 

 scrotum, analogous to the round ligament arising from the labium, and attached to 

 the ovary of the female.) which is originally attached to the vas deferens, gradually 

 fixes itself to the lower end of the tesiis or epididymis.* The Testes begin to de- 

 scend at about the middle period of pregnancy; at the seventh month they reach the 

 inner ring; in the eighth they enter the passage; and in the ninth they usually de- 

 scend into the scrotum. The cause of this descent is not very clear. It can scarcely 

 be due merely, as some have supposed, to the contraction of the gubernaculum; 

 since that does not contain any fibrous structure, until after the lowering of the testes 

 has commenced. It is well known that the testes are not always found in the scrotum at 

 the time of birth, even at the full period. Upon an examination of 97 new-born infants, 

 Wrisberg found both testes in the scrotum in 67, one or both in the canal in 17, in 8 

 one testis in the abdomen, and in 3 both testes within the cavity. Sometimes one or 

 both testes remain in the abdomen during the whole of life; but this circumstance does 

 not seem to impair their function. This condition is natural, indeed, in the Ram. 



698. The fluid secreted by the Testes is thick, tenacious, and of a grayish 

 or yellowish colour. It is mingled, during or before emission, with fluid 

 secreted by the Prostate, Cowper's glands, &c.; and it cannot, therefore, be 

 obtained pure, but by drawing it from the Testicle itself ; hence no accurate 

 analysis can be made of it in the Human subject. The so-called Spermatozoa 

 and Seminal Granules, which form the most important and characteristic parts 

 of the Semen, are so intimately connected with the Reproductive Function, 

 that they will be more appropriately described under that head (Chap. XIV). 

 It may be here remarked, however, that they correspond most exactly with 

 other Secretions, in their mode of production ; for, as will be shown hereafter, 

 they are elaborated by cells, which lie within the tubuli, and which rupture so 

 to set them free, when they are mature ( 735). The peculiar odour which 

 the Semen possesses, does not appear to belong to the proper spermatic fluid ; 

 but is probably derived from one or other of the secretions with which it is 

 mingled. The chemical analyses which have been made of this fluid are all 

 defective, inasmuch as they do not distinguish the real secretion of the testes 

 from the mucus, prostatic fluid, &c., with which it is mingled. It may be 

 stated, however, that it has an alkaline reaction, and contains albumen, with 

 a peculiar animal principle termed Spermatine ; and also saline matter, con- 

 sisting chiefly of muriates and phosphates, especially the latter, which form 

 crystals when the fluid has stood for some little time. 



VIII. Cutaneous and Mucous Follicles. 



699. Having now described the structure and functions of the principal 

 Glands, which are composed of aggregated masses of secreting cells or tubes, 

 we may proceed to those in which the glandule are more scattered, but are 

 still, in their aggregate amount, of sufficient importance to claim particular 

 notice. This is especially the case in the Skin, and its internal prolongations, 

 forming Mucous Membranes. ^The Skin is the seat of various secretions; for 



* Mr. Mayo mentions (Physiology, p. 430) a curious malformation that came under his 

 notice, which is explained by this fact. The left testis had not descended, and lay upon 

 the edge of the psoas muscle immediately within the internal ring; while the cord was 

 drawn down into the scrotum through the persistence of the original attachment of the 

 gubernaculum, forming a long loop. 



