884 GENERATION. 



of the vesiculse seminales, of the glands of the prostate, and of the glands of the urethra, 

 As we shall see when we come to discuss the mechanism of fecundation of the ovum, the 

 spermatozoids are the essential male elements, and these are produced in the substance 

 of the testicle, by a process analogous to that of the development of other true anatomi- 

 cal elements, and not by the mechanism with which we are familiar in secreting glands. 

 The testicles cannot be regarded strictly as glandular organs. They are analogous to the 

 ovaries, and they are the only organs in which spermatozoids can be developed, as the 

 ovaries are the only organs in which the ovum can be formed. If the testicles be absent, 

 the power of fecundation is lost, none of the fluids secreted by the accessory organs of 

 generation being able to perform the functions of the true fecundating elements. 



In the healthy male, at the climax of a normal venereal orgasm, from half a drachm 

 to a drachm of seminal fluid is ejaculated with considerable force from the urethra, by an 

 involuntary muscular spasm. This fluid is slightly mucilaginous, grayish or whitish, 

 streaked with lines more or less opaque, and it evidently contains various kinds of mucus. 

 It has a faint and peculiar odor, sui generis, which is observed only in the ejaculated 

 fluid and not in any of its constituents examined separately. It is a little heavier than 

 water and does not mix with it or dissolve. After ejaculation, it becomes jelly-like and 

 dries into a peculiar, hard mass, which may be softened by the application of appropriate 

 liquids. The liquid is not coagulated by heat and does not contain albumen. Its reac- 

 tion is faintly alkaline. It contains, in the human subject, from 100 to 120 parts of solid 

 matter per 1,000. 



The chemical constitution of the semen has not been very thoroughly investigated 

 and does not present the same physiological interest as its anatomical characters. Aside 

 from the anatomical elements derived from the testicles and the genital passages, it pre- 

 sents an organic principle (spermatine) which has nearly the same chemical characters as 

 ordinary mucosine. It also contains a considerable quantity of phosphates, particularly 

 the phosphate of magnesia. During desiccation, the characteristic crystals of this salt 

 usually make their appearance ; and, in the decomposed fluid, we frequently find crystals 

 of the triple phosphates. 



The composite character oi the seminal fluid will be better understood if we examine 

 briefly the properties of the different mucous secretions which enter into its composition. 



In the dilated portion of the vasa deferentia, the mucous glands secrete a fluid which is 

 the first that is added to the spermatozoids as they come from the testicles. This fluid is 

 brownish or grayish. 'It contains epithelium, and small, rounded granulations, which are 

 dark and strongly refractive. The liquid itself is very slightly viscid. In the vesiculee semi- 

 nales, there is a more abundant secretion of a grayish fluid, with epithelium, little color- 

 less concretions of nitrogenized matter, called by Robin, sympexions, and a few leucocytes. 

 The glandular structures of the prostate produce a creamy secretion, which contains nu- 

 merous fine granulations. It is chiefly to the admixture of this fluid that the semen owes 

 its whitish appearance. Finally, as the semen is ejaculated, it receives the exceedingly 

 viscid secretion of the glands of Cowper, a certain amount of stringy mucus from the 

 follicles of the urethra, with, perhaps, a little of the urethral epithelium. 



Anatomically considered, the seminal fluid contains no important elements except the 

 spermatozoids, the various secretions we have mentioned serving simply as a vehicle for 

 the introduction of these bodies into the generative passages of the female. We shall 

 therefore consider only the structure of the spermatozoids, their movements, and the pro- 

 cess of their development. 



Spermatozoids. In August, 1677, a German student, named Yon Hammen, discov- 

 ered the spermatozoids in the human semen, and exhibited them to Leeuwenhoek, who 

 studied them as closely as was possible with the instruments at his command. For along 

 time, they were regarded as living animalcules; though now they are considered simply 

 as peculiar anatomical elements, endov/cd with movements, like ciliated epithelium. 



