OF TRUE PREGNANCY. 129 



be heard in the womb of a pregnant woman: one, which aUhoiigh 

 quicker and shorter, is analogous to that of a feeble respiration, is 

 the bruit de soiijffie which he has denominated the placental sound; 

 the other, similar to the ticking of a watch wrapped up in cloths, 

 depends on the beating of the heart, and may be called the sound 

 of the heart. The former is isochronous with the pulsations of the 

 mother, which hinders it from being confounded with the respira- 

 tory sounds; but it is in almost every respect similar to that caused 

 by muscular contractions, that heard in the large arterial trunks 

 when spasmodically contracted or compressed by some external 

 tumor, and in the heart itself in certain pathological states*at pre- 

 sent not well understood; so that some well performed experiments 

 are still necessary in order to demonstrate that it appertains to preg- 

 nancy rather than to some other condition of the female. M. Ker- 

 garadec thought that it corresponded to the place where the placenta 

 is attached, and was produced by the passage of blood from the womb 

 to the vessels of the ovum, or in other words by the uterine or pla- 

 cental circulation; but although some facts seem to support this ex- 

 planation, there are many others opposed to it, and my own observa- 

 tions lead me to regard them as but very improbable conjectures. In 

 the majority of cases, it requires a very practised ear to perceive 

 them at all, and this is doubtless the reason which has induced many 

 physicians to reject them altogether. 



337. I have myself in vain sought for it in a great many subjects; 

 on the other hand I have distinctly heard it in a great many others. 

 It was sufficiently strong in three women who were confined at the 

 Hospital de Perfectionnement, and in two others who were made 

 use of for the practical demonstrations of my course, for the least 

 skilful medical students and female students in midwifery to hear it 

 very plainly. I have never met with it except in the second half of 

 pregnancy. If Laennec and M. De Lens, who say that they have 

 heard it before the end of the third month, were not mistaken, that 

 alone appears to me to be reason enough why it is impossible to at- 

 tribute it to the placento-uterine circulation. 



338. It should be sought for between the anterior edge of the 

 pelvis and the navel, and lower down in proportion as the pregnancy 

 is less advanced. 



339. The double-beat, or sound of the heart cannot be confounded 

 with any other; for the pulsations can be counted to the number of a 

 hundred to a hundied and forty or a hundred and fifty per minuie, 

 while the mother's pulse beats only from sixty to seventy-five in the 

 same space of time : growing stronger as the foetus grows older, 

 this sound can scarcely be appreciable before the fourth month; of 



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