414 



foetations is well proved ; they are ascribed to septa, dividing the uterus, 

 sometimes, into two cavities, merely because such an arrangement would 

 explain, to a certain degree, how two conceptions might take place, at 

 some interval from one another ; for it has never been ascertained, by 

 actual dissection, that any woman, in whom such superfoetations took 

 place, had a double uterus*. 



CCXX. Of suckling. Nothing is more generally known in physio- 

 logy, than the strict sympathy which subsists between the uterus and 



* It seems to me, that a belief in superfoetations can hardly be entertained by any one 

 who is conversant with the human economy, and particularly with the changes which 

 the uterine system undergoes in consequence of pregnancy. We know that soon after 

 conception, the os tincae, as well as the internal apertures of the fallopian tubes, are 

 closed by -a deposition of a thick tenacious mucus. But to accomplish still more per- 

 fectly an end so important to the scheme of" generation as the occlusion of the uterus, 

 nature resorts to another provision. 



By the sprouting forth of minute blood vessels*, or by the effusion of a species of 

 lymph-j-, or out of coagulated bloodt, a membrane of some firmness of texture is quick- 

 ly formed. This membrane, which is called decidua or caduca, from its being shed at 

 the period of delivery, lines completely the uterus, and thus co-operates with the dense 

 mucus already alluded to, in obliterating the three openings into its cavity. 



Such too, is the enlargement of the gravid uterus, and the change thereby produced 

 in the relative position of its appendages, that a new series of impediments arises to the 

 frustration of a second conception. 



In this state of the organ, it is accurately ascertained, that the tubes lie parallel to its 

 sides, and subsequently in the progress of gestation, become bound in the same situa- 

 tion, instead of running in a transverse direction towards the ovaries, with their extremi- 

 ties lower and fluctuating. 



Were an embryon, therefore, to be generated by any anamolous combination of circum- 

 stances, the tubes could not possibly embrace the fecundated vesicle, and the embryon, 

 of course, must remain in the ovary, or fall into the abdomen, constituting an extra 

 uterine conception. 



Let us, however, withdraw all the obstacles which have been enumerated to the pass- 

 age of the embyron, and admit the practicability of its reaching the uterine cavity. What 

 in this event would happen ? Disorganization'fatal to each foetus must ensue. 



It is to be recollected, that the uterus had prepared, in the first instance, whatever 

 was required for the reception, the nourishment, and evolution of the foetus. It had ori- 

 ginally supplied it with a decidua, as a medium of attachment, and afterwards with a 

 placenta for still more important purposes. For the second foetus, the same offices are to 

 be rendered. These it it could not execute, without suspending the action existing at 

 the time, and taking on such as are necessary to the fabrication of an additional deci- 

 dua and placenta. 



That actions so incompatible cannot co-exist, strikes me as sufficiently obvious. Were 

 the uterus, therefore, to attempt this new process, the result would be, the separation 

 of the primary decidua and placenta, occasioning an abortion, accompanied with haemorr- 

 hage, which would sweep out the whole of its contents. 



It is probably, on this account, that menstruation uniformly ceases with the accession 

 of pregnancy. I am aware, that this is a point not altogether conceded. The weight 

 of authority is however, decidedly against menstruation continuing dnring gestation. By 

 all the very recent writers it is denied. Those who hold, or I might rather say, did 

 hold the contrary opinion, have mistaken a hemorrhage from the vagina, which some- 

 times recurs with considerable periodical regularity, for the catamenial flux. Several 

 cases of this kind have come under my own observation, where I had an opportunity of 

 inspecting the discharge accurately. In every instance, I found it pure coagulable blood 

 having neither the colour, nor odour, nor any other of the peculiar properties of the 

 genuine menstrual fluid. 



Haller. f Dr. Hunter. * Mr. Hunter. 



