FALLOPIAN TUBE OR OVIDUCT (FUNCTIONS). 



duct, which it is necessary here to notice, is 

 the addition, sometimes, of a thick layer of 

 albumen around the zona pellucida, which is 

 formed upon it in the middle and lower por- 

 tions of the tube. BuUhis is certainly not a 

 constant, and apparently not even a common 

 occurrence. It occurs in the rabbit, but not 

 in the bitch, Guinea-pig, or roe. 



These are the principal and more obvious 

 changes which the ovum experiences in its 

 passage down the Fallopian tube until it 

 enters the uterus. So regular is the order 

 with which they succeed each other that 

 particular portions of the tube may be as- 

 signed as the seat of each occurrence*. Thus 

 the first, or upper third of the oviduct is 

 appropriated to the reception of the ovum, 

 which, soon after quitting the ovary, is here 

 deprived of its adventitious covering of nu- 

 cleated cells, and is thus prepared for the 

 full operation of the spermatozoa, whose 

 active movements in this part of the tube 

 have been frequently noticed. Here also 

 spermatozoa have been frequently seen upon, 

 and even within, the ova ; and here the first 

 changes characteristic of the commencing 

 operations of the sperm force, such as the 

 formation of the respiratory chamber, and 

 rotation of the yelk, may be noticed. In the 

 middle of the tube the ova commonly exhibit 

 still more decided evidences of impregnation. 

 The cleavage of the yelk has already com- 

 menced, and one or more granular bodies 

 occupy the space between it and the zona. 

 The ova found in the lower third, except 

 those which may be destined to perish, al- 

 ways show unmistakable signs of impregna- 

 tion, of which the segmentation of the yelk, 

 now advanced to the production of 12 16 

 divisions, is the most expressive. 



If the views of Bischoff be correct, it is in 

 the upper third, or at farthest in the middle 

 of the tube, that impregnation must occur, 

 unless indeed it takes place at the ovary. 

 For in the lower end of the tube the more 

 definite developmental changes of the ovum 

 occur, or otherwise the ovum perishes. In 

 the dog and Guinea-pig, by the time the ovum 

 has reached this spot, the oestrus is past, and 

 the animal will no longer permit the coitus.* 



Connected apparently with some of the 

 foregoing steps in the process of generation, 

 though it does not appear precisely with 

 which, is a phenomenon described by Bis- 

 choff as occurring in the Guinea-pig. Several 



* Pouchet (L'Ovulation Spontanee) places the 

 seat of impregnation lower down in the oviduct. 

 He asserts that it is only about the middle of the 

 tube, or more particularly in its lower portion, and 

 even in the cavity of the uterus itself, that the 

 material contact of the ova with the spermatozoa 

 can occur. And he regards the passage of the 

 semen as far as the extremity of the tube, and its 

 arrival at the ovary, as an " excessively rare ano- 

 malj-." But these statements are based upon ex- 

 aminations directed only to the detection of the 

 presence of spermatozoa in the oviduct, and are not 

 connected with microscopic observations of those 

 developmental changes in the ovum, which are in- 

 disputably the results of impregnation, and of which 

 an account has been given in the text. 



611 



times Bischoff had the good fortune to ob- 

 serve with a lens, and also under the micro- 

 scope, a peristaltic action in the walls of the 

 oviduct, by which the contained ova, visible 

 through them, were moved backwards and for- 

 wards. The ova appeared to be surrounded 

 by a transparent fluid, in which they floated. 



Now, such an observation is interesting, 

 when viewed in connexion with two circum- 

 stances, specially observed and proved by 

 Newport, namely, that in the artificial im- 

 pregnation of the ova of amphibia, although 

 the process of impregnation is commenced at 

 the instant of contact of the spermatozoa with 

 the ova, yet a certain duration of contact is 

 essential to its completion. And further, that 

 although an exceedingly minute quantity of 

 spermatozoa suffices to impregnate the ovum, 

 yet impregnation takes place more tardily 

 when the number is extremely limited than 

 when the number is in full abundance ; while 

 when the quantity is reduced below a certain 

 amount, or the duration of contact is limited, 

 then the phenomenon is incomplete, and 

 partial impregnation, evidenced by imperfect 

 segmentation of the yelk, and arrest of the 

 further stages of development, is the in- 

 evitable result. 



Since, then, it cannot be supposed that a 

 less perfect or complete contact of the ova 

 with the spermatozoa is needful to their im- 

 pregnation in the higher than in the lower 

 vertebrata, there seems to be good ground 

 for conjecturing that this peculiar peristaltic 

 movement in the walls of the Fallopian tube, 

 which has been noticed also by other ob- 

 servers, may have for one of its objects the 

 more perfect commingling of the two gene- 

 rative elements, the spermatozoa and the ova, 

 which, proceeding as they do in opposite di- 

 rections, and encountering each other in some 

 portion of the canal, would thus be carried 

 backwards and forwards, and thus a certain 

 permanence of contact, such as Newport has 

 shown to be necessary in the amphibia, would 

 be insured to them. And this supposition 

 may be further strengthened by the reflection 

 that while an onward movement in either di- 

 rection would serve for the conveyance of 

 each element singly along the tube, a back- 

 ward and forward motion alternating could 

 only retard either or both processes, and that 

 there could be only one apparent advantage 

 in such retardation, namely, the retention of 

 both elements for a longer or shorter time in 

 permanence of contact. 



To sum up the offices of the Fallopian 

 tube, the following may be said to have been 

 with certainty ascertained to belong to that 

 division of the generative organs : To re- 

 ceive the spermatic fluid from the uterus 

 and convey it upwards through the entire 

 canal, and as far sometimes as the ovary ; v 

 To receive contrariwise the unimpregnated 

 ova, as they are discharged from the ovary, 

 by means of its expanded open mouth, which 

 in these cases, where the entire ovary cannot, 

 be grasped, is guided, by a process hitherto 

 unexplained, to select and apply itself to that 

 R R 2 



