518 
MR. RAINEY ON THE STRUCTURE AND USE 
and the direction of their fibres, it is evident that their combined action will bring- 
the uterus nearer to the symphysis pubis, and thus tend to draw it somewhat from 
the vagina, in this way increasing the length of the latter. Now the only way in 
which I can imagine that these changes in the position of these parts assist in sexual 
intercourse, is by their causing the semen to be attracted more into the upper part of 
the vagina and vicinity of the os uteri. [Since the communication of this paper to 
the Royal Society I have been informed that this opinion is not new, but that this 
view of the use of the round ligament had been published by M. Velpeau*, and that 
it is also partly in accordance with that of MAVGRiERS-f.] This supposition seems to 
accord with the position and attachments of the round ligaments in those animals 
in which the uterus extends into the cavity of the abdomen beyond the brim of the 
pelvis, as was noticed in the Dog, the Sheep and the Cow, where their action would, 
obviously, be the same in drawing the uterus from the vagina, and in tending 
to elongate the latter, as in the human subject in whom the angles of the uterus are 
below the level of the broad ligaments. In such an act the muscular fibres of the 
round ligaments could scarcely be said to be voluntary ; but still they would be as 
much so as the other muscles concerned in the same process, that is, as those of the 
male organs of generation. In these instances muscles are said to act under excito- 
motory influence, but muscles which are thus excited have the same structure as 
those more obviously under the control of the will, namely, striped fibres. 
Some obser'vations upon the change which takes place in the Structure of the Uterus 
dialing Utero- gestation. 
The fasciculi of fibres composing the upper part of the round ligament separate as 
they approach the fundus of the uterus, become spread out over its surface, and ulti- 
mately blend with its fibres. Although the fibres of the round ligament are generally 
said to be of the same kind as those of the uterus, I have not been able to perceive 
much similarity, either with those of the unimpregnated or the impregnated uterus, 
the fibres in both these states of the uterus being peculiar. The proper tissue of the un- 
impregnated uterus is so remarkably dense that there is considerable difficulty in un- 
raveling it sufficiently to display the true character of its fibres, and sections thin 
enough to admit of being seen as a transparent object by the microscope, give no 
distinct idea of its real nature. Its characters can be best understood by breaking 
up portions of the uterus with needles, and examining them in glycerine, but still 
they should be first seen in water ; also the arteries of the uterus should be fully in- 
jected (these are remarkably tortuous, and possessed of very thick coats), otherwise 
the tissue of the small vessels, and the nuclei in the coat of the capillaries, may be 
examined instead of, and mistaken for, the proper fibre of the uterus. Any part of 
the unimpregnated uterus, after having been thus treated, will be seen to be made up 
* Anatomie Chirurgicale, 1833, vol. ii. p. 372. 
t Nouvelles Demonstrations d’Accouchements, p. 62. 
