The uterine souffle taken by itself, although a very valuable sign of pregnancy, can scarcely be looked upon as one which is perfectly certain and diagnostic, since a similar sound may be produced by aneurism of the abdominal aorta and its large branches: there is much reason to think that the uterus, enlarged from other causes than that of pregnancy, and pressing upon the iliac arteries, will produce a similar sound. Professor Naegelé, jun., has also shown that the sounds of the patient's heart may sometimes be heard very low in the abdomen, even as far as the ossa ilii, a circumstance which seems to have depended upon the sound being transmitted through the intestines distended with flatus. Where any of these causes of abdominal souffle have existed in connexion with suppressed catamenia, swelling of the breasts, &c., we might be liable to be deceived if we allowed ourselves to be entirely guided by this sound. With regard to the foetal pulsations, we find them generally beating at the rate of from 130 to 150 double strokes in a minute, and the age of the foetus appears to have no effect upon their rapidity, for even at the earliest periods at which we can detect these sounds the rate of the pulsation is the same as at the full term of pregnancy. Although Dr. Kennedy has in a few cases detected this sound even before the expiration of the fourth month, it will not in the majority be possible until a later period. "At the fourth month it frequently requires not only close attention, but considerable perseverence to detect the foetal heart; and at this period it has occurred to us to examine patients whom there was strong reason to suppose pregnant, and after spending a considerable time in endeavouring to detect this sound, we have been on the point of giving up the search as hopeless, when it has been suddenly discovered in the identical spot that had before perhaps been explored without success." (Kennedy, _op. cit._ p. 101.)