608 



UTERUS AND ITS APPENDAGES. 



oviduct, the ovum may not become impreg- 

 nated until after it has reached the principal 

 cavity of the generative track. 



In order, therefore, to determine as nearly 

 as possible the precise limits of the functions 

 of the oviducts, it will be necessary to ex- 

 amine more particularly the evidence, which 

 serves to show, that while the ovary is the 

 part in which the ovum is formed, and the 

 uterus that in which it is developed ; the 

 Fallopian tube, besides being the conductor 

 of the ovum from the formative to the reci- 

 pient organ, is also the seat of the second 

 most important step in the process of genera- 

 tion, namely, its fertilisation. 



Here human physiology is so much at fault 

 that it again becomes necessary to resort to 

 the evidence furnished by experiments, and 

 observations made upon the mammalia ge- 

 nerally. 



Now, one of the most remarkable circum- 

 stances relating to the generative process in 

 the mammalia is, that the periods of separa- 

 tion of the ova from the ovary, and of their 

 passage down the Fallopian tube, are coinci- 

 dent with the oestrus. Bischoff^ indeed, has 

 ascertained, in the bitch, that by the time the 

 ovum has reached the uterus, or even the 

 lower end of the oviduct, the period of heat, 

 or desire for sexual congress, has passed 

 away, and consequently the opportunity for 

 impregnation is lost. In the Guinea-pig also 

 it appears certain that the opportunity for 

 impregnation is already gone by the time the 

 ovum has quitted the tube, and has reached 

 the uterus ; for the oestrus is then long 

 passed, the coitus has long ceased to be 

 permitted, and even the vulva is at this time 

 again contracted. And although doubtless 

 these conditions vary in different genera, yet 

 a variety of circumstances, of which a more 

 particular account will be presently given, 

 renders it probable that the rule is general 

 among the mammalia, that insemination shall 

 occur coincidently with the passage of the 

 ovum down the Fallopian tube. 



Next, it may be shown, by the experiments 

 of Cruikshank, Haighton, Blundell, and 

 Bischoff, which consisted in deligation or 

 excision of portions of the tube, that when- 

 ever the obliteration of the canal was com- 

 plete, and had been effected prior to the act 

 of copulation, fertilisation of the ovum was 

 rendered impossible. 



These experiments were most satisfactory 

 when performed on one side only of the ge- 

 nerative organs, so as to leave free play for 

 the natural functions of the other ; and thus 

 the negative results obtained on the one half 

 of the body being set off against the positive 

 ones of the other, served to enhance the 

 value of both. By such experiments it may 

 be shown, that mechanical obstruction of the 

 tube, while interfering in no respect with the 

 spontaneous separation of the ovum from the 

 ovary, or its reception by the mouth of the 

 tube, and descent as far as the seat of ob- 

 struction (provided indeed that care is taken 

 in the experiment not to destroy the vascular 



supply of the parts), prevents the completion 

 of the reproductive act, and stops it at this 

 stage, by impeding the access of the sper- 

 matic fluid to the ovum. 



But the results of such experiments will 

 necessarily vary according to the time and 

 place of application of the ligature. Thus 

 while division or deligation of the tube before, 

 or even very shortly after, intercourse pre- 

 vents impregnation of the ova, yet, according 

 to Haighton, the same experiment performed 

 sixty hours after coitus had no effect what- 

 ever in impeding the development of the em- 

 bryo, for in that time the encounter of the 

 generative elements would have already taken 

 place. 



But although these experiments may be 

 infinitely varied, they cannot afford such sa- 

 tisfactory information as may be derived from 

 the actual examination of the contents of the 

 tube where natural impregnation has been 

 allowed to obtain, especially when these exa- 

 minations have been conducted with the aid 

 of the microscope. In this way may be ob- 

 tained an amount of collective evidence that 

 leaves little to be desired for the purpose of 

 fully elucidating the history of the ovum dur- 

 ing that brief but important period which 

 intervenes between its quitting the ovary and 

 its entrance into the uterus. But since an 

 account of the development of the ovum does 

 not come within the scope of this article, 

 only so much of the subject will be given 

 here as will be requisite to continue the ar- 

 gument for the purpose of showing what is 

 the precise part which the Fallopian tube 

 takes in the process of impregnation. 



There can be no question that the mam- 

 malian ovum, after an efficient coitus, enters 

 the uterus in a condition differing in many 

 important particulars from that in which it 

 ordinarily quits the ovary. And although a 

 certain amount of variation is perceptible in 

 regard to the actual changes experienced by 

 the ovum in different species, during its pas- 

 sage through the tube, yet so constantly are 

 the main features preserved, that the obser- 

 vations made upon any one species will ge- 

 nerally serve as a type of the rest, and cer- 

 tainly the aggregate of these observations, 

 agreeing closely as they do with one another, 

 render the conclusion in the highest degree 

 probable, that changes not very different from 

 these occur also in the ovum in man. 



Barry asserts that " there is no condition 

 of the ovum, uniform in all respects, which 

 can be pointed out as the particular state in 

 which it is discharged from the ovary." Ne- 

 vertheless the ripe ovum which is about to 

 be expelled, or one which has been just 

 discharged, presents certain well-marked cha- 

 racteristics, of which the following are the 

 most important. 



The ovum is closely invested by a layer of 

 nucleated cells. These form a portion of the 

 granular membrane or lining of the Graafian 

 follicle in which it is imbedded, and when 

 the ovum is discharged from the follicle, as 

 described at p. 560., a portion of these gra- 



