Obstetrical auscultation should generally be undertaken with the woman occupying the dorsal position, the legs being extended or the thighs flexed. In some cases the lateral decubitus is advantageous. The stethoscope should always be used, and it is generally advisable to apply it directly to the abdominal wall, in order that auscultatory signs may be clearly and directly transmitted. The stethoscope should be neither too long nor too short, and should have an end-piece sufficiently large to cover consider • able surface on the abdominal wall. The auricular extremity should be sufficiently large, and should possess such a shape as to easily adapt itself to the ear. It should be placed perpendicularly to the abdominal parie tes, and should be maintained in position by the aecoucheur's head alone. Maygrier suggested vaginal auscultation. Nauche even devised a special stethoscope for this purpose, and called it a metroscope, but the princi ple and the instrument had been forgotten, when they were recently re vived by Verardini. This method is not likely to become popular, for very few women would submit to it, while none reject abdominal auscultation. On auscultating the abdomen of a pregnant woman, one perceives several sounds, some of which are maternal, while some are festal. Some of these sounds are independent of pregnancy, as, for example, the gurgling of the intestines, the muscular fremitus, and the sounds originating in the maternal circulatory apparatus, whether in the heart or in the large pel vic vessels. Other sounds are directly dependent upon pregnancy. These are the uterine souffle, the foetal heart sounds, the foetal or umbilical souffle, and the sounds due to active foetal movements. We consider the sounds emanating from the foetus only as certain signs of pregnancy.
1st. The Uterine Souffle.
The uterine souffle, at one time considered a certain sign of pregnancy, has been robbed of its importance by the discovery that it may be devel oped in any unimpregnated uterus which has become notably enlarged. Nevertheless, since pregnancy is the most frequent cause of uterine en largement, since the uterine souffle always coexists with pregnancy, the presence of the souffle should always suggest the possibility of existing pregnancy. The uterine souffle has been successively designated by the terms, simple pulsation with souffle (Lejumeau de Kergaradec), placental pulsation (Ulsamer, Kohl), simple pulsation (Ritgen), placental souffle (Monod), abdominal souffle (Bouillaud), bellows sound (Kohl), epigastric souffle (Kiwisch), uterine bruit (Ntege16), uterine souffle (Dubois and Depaul.) Character of the Soufite.--The souffle is most frequently slightly vibra tory, and separated by a short, yet distinct interval from the succeeding sound, but its chief peculiarity is its occurrence synchronously with the maternal pulse. It may possess either a sonorous or a sibilant quality, but its cycle is separable into three distinct periods, viz.: A period of in ception, one of maximum intensity, and one of subsidence. The last period is much longer than the others, and ends in the complete cessation of the souffle. Moreover, it is never accompanied by pulsations as are the other abdominal souffles. It is thus a simple souffle, without pul sations, and isochronons with the mother's pulse. The souffle is generally appreciable at the beginning of the second half of pregnancy, at four and one-half months, but it has been heard earlier, and, in some exceptional cases, Depaul was able to appreciate it during the twelfth and in one case even in the tenth week. Depaul says that there is no part of the uterus at which the souffle may not be heard, but that it is perceived most plainly at the lateral and inferior parts. Early in pregnancy it is, how ever, best heard in the median line, above the pubes. It is not always
heard at the same point, nor is it constant. The intensity of the souffle usually increases with advancing utero-gestation, at least up to the seventh month. After that time, the difference is less marked. Depaul does not believe that the intensity of the souffle is proportionate to the intensity of the maternal cardiac action, but considers it stronger in multiparEe. He thinks that the sound is directly influenced by the pressure of the stethoscope, by the foetal movements, and especially by uterine contrac tions, which may cause it to entirely disappear. What is the cause of the uterine souffle, what is its seat, and what its mechanism ? The oldest theory is that of Hans, who attributed the souffle to pressure of the uterus upon the aorta and the iliac arteries. Adopted by Bouillaud, this theory has since been combated by almost all authors, and recently by Tarnier and Chantreuil. The theory of Laennec and Carriere, advocated by Monod and Hohl, referred the souffle to the placenta, This theory was completely demolished by Bailly, who showed that the souffle persists not only after the expulsion of the foetus, but, on the average, for two or three days after delivery, and that, in certain rare cases, it can be heard up to the sixth day. The souffle has also been heard in cases of uterine enlargement from fibroids (Charcot). [As also over ovarian cysts.—Ed.] We owe to Paul Dubois the theory at present accepted, with few modifications, by all obstetricians, and which we ourselves adopt. P. Dubois first established the fact that the souffle could only occur in the uterine walls, and, " having observed that the uterine souffle strongly re sembles the vascular murmur which results in an aneurismal varix, from the passage of blood from an artery into a vein, he announced that nu merous direct communications exist between the arteries and the veins of the uterus, the walls of which seem formed by a tissue of natural aneur isms, and that the arterial blood, passing directly into the veins, is min gled with the less rapidly circulating venous currents." Dubois, there fore, refers the origin of the souffle to the mingling of the arterial blood with the venous blood, which circulates more slowly. (Depaul). Ntegele denies that it results from the commingling of arterial and venous blood, and locates the bruit in the arteries. Jacquemier denies the existence of direct communications between the arterial and venous radicles, and re turns to Bouillaud's theory. Stoltz admits that the souffle originates in the uterine walls, but locates it in the sinuses, situated at the level of the placental insertion. Laharpe and Cazeaux find the cause in the multipli cation of vessels in the uterine tissue. Depaul shares the opinion of Du bois, that the souffle is produced in the uterus. The bruit is so super ficial that it is evidently produced in the uterine walls. Pajot, Blot, Rotter and Rapin adopt this view, but, for Depaul, the varying calibre of the uterine arteries is the real cause of the souffle. Calling attention to the greater capacity of the veins, he shows that the volume of blood brought by the uterine arteries must be insufficient to fill all their branches, provided that the efflux of blood from the veins be unobstructed. Re calling, also, the fact that liquids circulating in tubes produce no sound, if the tubes are filled, and are of equal calibre throughout, but do cause a bruit under the opposite conditions, Depaul shows that, at the place where the arteries penetrate the uterus, they dilate, and acquire a capacity • so great, that the incoming blood is not sufficient to fill them. This dis proportion may be produced by different causes, the most common of which seems to be the compression exerted from within outward by the prominences of the foetal ovoid.