672 



UTERUS AND ITS APPENDAGES. 



whose free ends moving rapidly, cause the 

 whole to rotate. A most remarkable object 



Fig. 459. 



Spermatozoa of Lumbricus agricola in motion and 

 forming cilia. (Ad iVai.) 



is thus formed, which continues for a con- 

 siderable time in motion, clearing for itself a 

 free area, and in this it revolves, whilst its 

 revolutions are apparently assisted by the ac- 

 tion of other spermatozoa, which, having at- 

 tached themselves to the periphery of the 

 cleared space, keep up a perpetual vortex, in 

 which the central body is partly a passive and 

 partly an active agent.* 



Whether any similar effect is capable of be- 

 ing produced by the spermatozoa in the human 

 subject, or how far this property may be ge- 

 neral in spermatozoa, I am not aware ; but 

 the circumstance is altogether too remarkable 

 to be passed over without mention here, as it 

 may serve to explain how the onward move- 

 ment of spermatozoa can, in some cases at 

 least, be aided by this peculiar property of the 

 spermatic filaments to attach themselves to 

 surfaces with which they were in contact, and 

 to clothe these surfaces with a fringe of cilia 

 capable of producing the ordinary effects of 

 cilia in motion. 



The office of the uterus in gestation. The 

 process of gestation may be considered to 

 commence from the moment that the ovum, 

 which has been subjected to the fertilising in- 

 fluence of the male generative element in the 

 Fallopian tubef, is received impregnated into 



* These observations were first made by me at 

 the time when the late Dr. Martin Barry announced 

 his discovery of the penetration of the ovum by the 

 spermatozoa in the rabbit, and were communicated 

 to him, and subsequently for publication to Prof. 

 Owen, in whose lectures on the invertebrata this 

 account appears. Lectures on the Comp. Anat. and 

 Phys. of the Invertebrate Animals, by Richard 

 Owen, F.R.S., 2nd edit. p. 257. 



t Seep. 009. 



the uterine cavity. If no such contact of the 

 generative elements as is necessary to the de- 

 velopment of the ovum takes place, then the 

 latter suffers no further change beyond that 

 slight alteration in its condition during its 

 passage through the oviduct, which has been 

 already described ; and ultimately it becomes 

 lost, probably suffering decomposition, but at 

 least giving no evidence of its presence in the 

 uterine cavity. But if the ovum lias been fer- 

 tilised, then commences that remarkable series 

 of changes in the physical condition of the 

 uterus whereby this organ is fitted for the pro- 

 tection and nutrition of the ovum during the 

 usual period of forty weeks in which the latter 

 is normally retained within its cavity. As these 

 changes involvevery considerable alterations in 

 the form and composition of the entire uterus, 

 as well as of its several parts, they have been 

 considered as a part of that series of meta- 

 morphoses which the uterus undergoes in its 

 progress from infancy to old age, of which a 

 description has been already given, (p. 644.). 

 The office of the uterus in parturition. The 

 act of parturition, or that process by which, 

 in normal cases, the product of conception, 

 after due development, is spontaneously sepa- 

 rated and expelled from the parent body, con- 

 stitutes the last chief office of the uterus. 



The labour process may be regarded as es- 

 sentially a contest between two opposing 

 forces, which are resisting on the one hand, 

 and propulsive on the other. Resistance is 

 necessary to preserve the foetus in its place. 

 Propulsion is requisite to detach and expel it 

 from the parent body. The resisting force is 

 chiefly passive in its operation. It is that 

 which is offered by the membranes enclosing 

 the fcetus, by the os and cervix uteri, by the 

 soft parts lining and closing in the pelvis, and 

 lastly by the osseous and ligamentous struc- 

 tures of the pelvis itself. Naturally, these are 

 sufficient to counteract any tendency to the 

 escape of the fcetus from the operation of 

 gravity upon it, in various changes of posture, 

 or under any impulsive movements of the 

 parent body. Their combined resistance is such 

 as to require the operation of powerful mus- 

 cles to overcome them before the child can be 

 expelled. This power is supplied by the uterus, 

 aided subsequently by the diaphragm and 

 other muscles, abdominal and pelvic. Labour 

 constitutes the performance, and birth the 

 end of the process, for the accomplishment of 

 which in a natural manner the forces should 

 be nearly evenly balanced. The preponde- 

 rance of power being, however, at first, on the 

 side of resistance, and finally on that of pro- 

 pulsion. Whenever the forces are thus pro- 

 portioned, the act of parturition is, caiteris 

 paribus, natural. Whenever they are greatly 

 disproportioned, the process is abnormal ; 

 whether the error be on the side of too much 

 resistance, or too little propulsive force. In 

 these last two particulars may be compre- 

 hended the history of every unnatural labour 

 in which the mechanism* is at fault. 



* The mechanical operation of the parts con- 

 cerned in labour having been reserved for con- 



