UTERUS (FUNCTIONS). 



blooil. And thus, by each act of menstrua- 

 tion, the uterus is placed in a state of prepa- 

 ration for that profuse development of its 

 tissues which impregnation may at any time 

 of the succeeding interval call forth. 



The office of the uterus in insemination. 

 After menstruation, which is to be regarded as 

 a process preparatory to impregnation, the 

 next office of the uterus is that of receiving 

 the seminal fluid, and apparently of conducting 

 it to the Fallopian tubes, by which again it 

 may, in rare instances, be carried as far as the 

 ovary. To this office the form of the uterus 

 appears to be well adapted in all its parts. 

 For, first, the cervix uteri is so constructed as 

 to lie in the centre of the upper dilated portion 

 or fornix of the vagina, into which it projects 

 to a distance of 3 4 . This dilated ex- 

 tremity of the vagina forms a pouch which re- 

 ceives the extremity of the intromittent organ, 

 and in this receptacle the seminal fluid is de- 

 posited. But, on account of the natural posi- 

 tion of the uterus, which lies in the axis of the 

 pelvic brim, while the course of the vagina 

 corresponds with that of the cavity and out- 

 let (fig. -133. ), the cervix uteri is so directed 

 (downwards and backwards) as to cause the 

 os uteri externum to be maintained in the 

 very centre of this pouch, so that the seminal 

 fluid will be retained in a situation in which it 

 is most certain to flow through this orifice into 

 the cervix.* But the cervical canal is traversed 

 by numerous furrows, which will act as so many 

 channels, conducting the semen to the internal 

 os, while the dilated central portion of that 

 canal (fig, 424.) serves the purpose of a second 

 reservoir. 



It may also be readily believed that the 

 ejaculatory act on the part of the male will 

 suffice to carry the seminal fluid thus far, 

 although the impetus with which it is propelled 

 having been checked by the constriction caused 

 by the external os uteri, would hardly suffice 

 to carry it much beyond the more narrow bar- 

 rier existing at the internal os. Or if it should 

 pass this second obstacle, the almost complete 

 apposition of the walls of the uterus would 

 prevent any considerable penetration of the 

 semen further into the uterine cavity, so far as 

 this is dependent on the act of ejaculation. 



But this very apposition of the uterine walls 

 may, in another manner, assist the onward 

 progress of the semen, by inducing a kind of 



* Dr. James Blundell has described a peculiar 

 movement which he observed in the vagina of the 

 rabbit, and which serves to explain the mode of in- 

 troduction of the seminal fluid into the uterus: 

 " This canal during the heat is never at rest ; it 

 shortens, it lengthens, it changes continually in its 

 circular dimensions ; and when irritated especially 

 will sometimes contract to one-third of its quiescent 

 diameter. In addition to this action the vagina 

 performs another," which " consists in the failing 

 down, as it were, of that part of the vagina which 

 lies in the vicinity of the wombs ; so that it every 

 now and then lays itself as flatly over their orifices 

 as we should apply the hand over the mouth in an 

 endeavour to stop it. How well adapted the whole 

 of this curious movement is for the introduction of 

 the semen at the opening it is needless to explain." 

 Researches Phys. and Pathol. p. 55. 1825. 



671 



capillary attraction, such, for example, as will 

 cause water to rise, to a certain distance, be- 

 tween two plates of glass placed in close con- 

 tact. The rigid walls of the human uterus, 

 which are normally in such close apposition 

 that sections made in certain directions scarcely 

 suffice to display any appreciable cavity (figs. 

 426. and 427.), seem admirably adapted to fa- 

 vour this gradual rise of the seminal fluid be- 

 tween them towards the Fallopian tubes ; and 

 thus a compensation is provided for that peri- 

 staltic movement, which, in some mammalia 

 with a more intestiniform and less rigid uterus, 

 appears, under the influence of the coitus, to 

 affect alike the vagina, uterus, and Fallopian 

 tubes*, and to suffice for the conveyance of the 

 seminal fluid from one extremity to the other 

 of the generative track. 



The action of the cilia of the uterine epi- 

 thelium cannot, in any way, contribute to this 

 result, if those observations are correct which 

 agree in assigning to them a movement such 

 as would create a current from within out- 

 wards ; for it is obvious that such a motion 

 would tend to retard rather than to advance 

 the progress of the seminal fluid towards the 

 Fallopian tubes. 



If therefore any other power is needed to 

 account for this movement, it must be sought 

 in the action of the spermatic particles them- 

 selves. For, little adapted as their motions 

 appear to anything like onward progression, 

 yet they have been observed to continue long 

 after ejaculation, in the fluid found within the 

 uterus and tubes, and even upon the ovary.-f- 

 It has been also proved beyond doubt that by 

 this power the spermatozoa penetrate the ovum 

 itself J, and therefore to it may be attributed 

 a certain share in the progress of the seminal 

 particles through the uterus towards the ovi- 

 ducts, although this may not be a very con- 

 siderable one. 



Finally, it is possible that in man and the 

 mammalia some such remarkable property may 

 be possessed by the spermatozoa as that which 

 I have observed in certain annellides. If a 

 portion of the contents of the testis of the com- 

 mon earth-worm (Lunibricns agricola, Hoffm.) 

 be placed under the microscope between two 

 slips of glass, in about ten minutes the whole 

 mass is seen to heave and writhe with aston- 

 ishing energy, the form of the movement being 

 that of the peristaltic action of the intestines 

 (fig. 459.). Everything in contact with the 

 spermatozoa becomes ciliated by them, one end 

 of the filament fixing itself while the other 

 vibrates free. The result is, that if the body 

 to which the spermatozoa attach themselves 

 is fixed, such as the glass, or the margin of a 

 mass of granules, a line of cilia is formed whose 

 action creates a strong current, and everything 

 movable is drawn into the vortex, and is seen 

 drifting rapidly along. But if the body to 

 which they attach themselves is movable, then 

 this soon becomes clothed with spermatozoa, 



* Blundell foe. cit.; see also p. Gil. of this 

 article. 



1 See this article, p. 607. 



j Newport, Phil. Trans. 1853. Pt. II. p. 267. 



