A few years ago, Glenard of Lyons, readopting a theory advanced by Biwisch as early as 1849, admitted that the souffle was produced in the epigastric artery. Then, forced to surrender by the objections of Tarnier and Depaul, he abandoned the epigastric artery, and located the bruit in an artery situated in the antero-lateral part of the uterus, to which he gave the name of puerperal artery. This was a reversion to the uterine theory. It is then the theory of Dubois, modified by Depaul, which is now generally adopted. To recapitulate: The uterine souffle is a simple blowing sound, synchronous with the maternal pulse, never accompanied by a pulsation, which fact distinguishes it from the other blowing sounds which are sometimes heard in the heart or in the great vessels. Although the souffle is not a certain sign of pregnancy, it is one of great probabil ity, since pregnancy is the state which most frequently developes the uterus, and its vascular organs.
2d. The Fcetal Heart-Sounds.
Like the ticking of a watch, the foetal cardiac pulsations are composed of two distinct sounds separated by a short interval. The first sound is stronger, and more sonorous than the second, which is sometimes very weak, but always audible if the child be healthy. The sounds are heard, according to Depaul, after the end of the third month. We must con fess that we have never heard them before the middle of the fourth month, which agrees with the majority of authors, who state the middle of the fourth month as the time of their appearance. After the time mentioned, we have always heard them in all the cases in which we sought for the sounds, if the infant were living. Owing to the great mobility of the fcetus, in the early months the heart-sounds are naturally heard at differ ent points, but as the fcetus tends to assume a fixed position in proportion to its development, the point at which the sounds will be best heard will be that which is nearest to the festal heart. The foetal cardiac pulsations will thus present their maximum intensity at this point, and will diminish proportionately to the remoteness from this point. The average fre quency of the heart-beats is from 135 to 140. It is not, however, rare to find children whose hearts beat only 120 times, and others whose heart beats number 150. Pepaul even found one healthy babe whose heart beats were 160 per minute. The heart's action may, in the same fcetus, be accelerated or retarded, in the former case by stimulation of the fcetus, and in the second by uterine contractions. This retardation is never more marked than during parturition. During labor, the pulsations are accele
rated slightly at the beginning of a pain, then they are retarded and di minished in force, even almost completely disappearing during the con traction, but resuming their normal rhythm as the pain diminishes and disappears.
The life of the fcetus is generally not endangered by the inhibition of the heart. If, however, the uterine contractions be too energetic or too frequent, they may imperil the life of the fcetus. In one case of our own, two years ago, the child was stillborn, after a labor of only two hours. The mother was a primipara. Ten minutes before delivery, the foetal heart was beating, but the final pains were so extremely energetic and continuous that the child was born dead, and could not be resuscitated by insuftlation. The rapidity of the expulsion prevented us from thinking of interference, and our disappointment was the more intense because nothing pointed to the disaster.
The force of the heart-beats varies with the strength of the fcetus, its development, and the greater or less facility with which one hears the sounds. The thickness of the abdominal walls, the greater or less quantity of the amniotic fluid, and the position of the fcetus, are all conditions which must be taken into account. The frequency of the heart-beats bears no relation to the rapidity of the maternal pulse, except when the temperature of the mother exceeds a certain point. Winckel, Runge, and later German authors, have shown that, when the maternal temperature is raised beyond 102.1°, the festal heart action is notably accele rated, and that, when the temperature reaches 104.2°, the fetuses almost always die after having presented an enormous acceleration of their car diac pulsations. The maternal heart-beats are not easily mistaken for those of the fcetus, even when presenting considerable acceleration. The differential diagnosis is easily made, if a little care is exercised, the maxi mum intensity corresponding to the prtecardium. If the sounds emanate from the mother's heart, their intensity will diminish as the stethoscope is removed from the mother's cardiac region, and the reverse. There is also a point of maximum intensity for the festal sounds, but between these two points the auscultator will always find a point of minimum intensity for both sounds, and, according as a given sound is maternal or foetal, it will grow plainer in proportion as the stethoscope approaches the thorax or the abdomen of the mother respectively.