ACTION OF THE FEMALE. 707 



having been falsified by the extravasation of fluid, consequent upon the force 

 used in injecting the vessels. Moreover, the different size of the blood-corpus- 

 cles in the Foetus and in the Parent ( 149) shows the non-existence of any 

 such communication. 



925. The formation of the Placenta, in the manner just described, com- 

 mences in the latter part of the second month ; during the third, it acquires 

 its proper character; and it subsequently goes on increasing, in accordance 

 with the growth of the ovum. Towards the end of the term of gestation, 

 however, it becomes more dense and less vascular; owing, it would seem, to 

 the obliteration of several of the minuter vessels, which are converted into 

 hard fibrous filaments. The vessels of the Uterus undergo great enlargement 

 throughout, but especially at the part to which the Placenta is attached; and 

 the blood in moving through them produces a peculiar murmur, which is 

 usually distinctly audible at an early period of Pregnancy, and may be regarded 

 (when due care is taken to avoid sources of fallacy), as one of its most unequi- 

 vocal positive signs. The Placental bruit is thus described by Dr. Mont- 

 gomery.* " The characters of this phenomenon are, a low murmuring or 

 somewhat cooing sound, resembling that made by blowing gently over the lip 

 of a wide-mouthed phial, and accompanied by a slight rushing noise, but with- 

 out any sensation of impulse. The sound is, in its return, exactly synchronous 

 with the pulse of the mother at the time of examination ; and varies in the 

 frequency of its repetitions, with any accidental variation which may occur 

 in the maternal circulation. Its situation does not vary during the course of 

 the same pregnancy ; but in whatever region of the uterus it is first heard, it 

 will in future be found, if recognized at all, for it is liable to intermissions, 

 at least we shall occasionally be unable to hear it where we have already 

 heard it a short time before, and where we shall shortly again recognize it. 

 According to my experience, it will be most frequently heard about the situa- 

 tion of the Fallopian tube of the right side ; but it may be detected in any of 

 the lateral or anterior parts of the uterus." That the cause of this sound 

 exists in the Uterus itself, is distinctly proved by the fact, that it has been 

 heard when that organ was so completely anteverted, that the fundus hung 

 down between the patient's thighs. A sound so much resembling this, as to 

 be scarcely distinguishable from it, may be occasioned, however, by a cause 

 of a very different nature, namely, an abdominal tumour, pressing upon the 

 aorta, iliac arteries, or enlarged vessels of its own; and, in doubtful cases, it 

 is necessary to give full weight to the possibility of such an explanation. The 

 sound may be imitated at any time, by pressing the stethoscope on the iliac 

 arteries. The Placental bruit has been not unfrequently heard in the llth 

 week ; but it cannot generally be detected before the fourth month, when the 

 fundus uteri rises above the anterior wall of the pelvis. 



926. The amount of the peculiar tissue of the Uterus ( 234) greatly 

 increases during pregnancy. At the same time, the Mammary gland and its 

 appendages undergo a fuller development; and from this a valuable, but not 

 unequivocal, indication of pregnancy may be drawn. Occasional shooting 

 pains in the Mammae are not unfrequently experienced within a short period 

 after conception ; and more continued tenderness is also not unusual. A sense 

 of distension is very commonly experienced at about the end of the second 

 month; and from that time a distinct " knottiness" usually begins to present 

 itself, increasing with the advance of Pregnancy. In many instances, how- 

 ever, these mammary sympathies are entirely absent; and they may be simu- 

 lated by changes that take place in consequence of various affections pf the 

 Uterus. A change of colour in the areola is a very common, but not an 



* Op. cit., p. 121. 



