The physiology of the circulation in plants, in the lower animals, and in man : being a course of lectures delivered at the Surgeons' Hall to the president, fellows, etc. of the Royal College of Surgeons of Edinburgh, in the summer of 1872 / by J. Bell Pettigrew.

  • Pettigrew, James Bell, 1834-1908.
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: The physiology of the circulation in plants, in the lower animals, and in man : being a course of lectures delivered at the Surgeons' Hall to the president, fellows, etc. of the Royal College of Surgeons of Edinburgh, in the summer of 1872 / by J. Bell Pettigrew. Source: Wellcome Collection.

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    the valves and into the cavities and vessels of the heart, constitute the major factors, the opening and closing of the valves the minor. The Dublin committee, appointed to investigate this matter, concluded that the first sound is produced either by the rapid passage of the blood over the irregular internal surface of the ventricles on its way towards the mouth of the arteries, or by the bruit vmsculaire (susurrus) of the ventricles, or probably by both of these causes. The London committee, appointed for a like purpose, came to similar conclusions. It found that the sound produced by the contraction (shorten- ing) of the abdominal muscles, as heard through a flexible tube, resembles the systolic sound, and that the impulse of the heart against the chest in certain positions of the body intensified this sound. M. Marc D'Espine maintained that both the first and second sounds depend on muscular move- ments—the first sound upon the systole and the second upon the diastole of the ventricles. D'Espine, it will be observed, attributes sound both to the diastole or opening of the ventricles, and to the systole or closing of them, and in this I think he is perfectly correct—the opening and closing of the different parts of the heart, as I have en- deavoured to show, being equally vital movements. That muscle invariably produces sound during its action is well known; and that a powerful compound muscle like the heart, with fibres interlacing in every direction, should, when closing and opening in hollow cavities such as the pericardium and thorax, produce audible and characteristic sounds, is what we would a priori expect. That sound may be produced by the impinging of fluids against animal tissues, or by the trituration of the particles of the fluid itself, can be proved by direct experiment. Valentin, e.g., showed that if a portion of a horse's intestine be tied at one end, and moderately distended with water without any admixture of air, and a syringe containing water be fixed into the other end, by pressing the piston of the syringe down, and forcing in more water, the first sound is exactly imitated. When, on the other hand, the aortic or pulmonic valves are diseased, their surfaces roughened, and the apertures which they guard diminished, the character of the first sound is altered.