Diseases of the heart and arterial system : Designed to be a practical presentation of the subject for the use of students and practitioners of medicine.
- Babcock, Robert H. (Robert Hall), 1851-1930
- Date:
- 1910
Licence: Public Domain Mark
Credit: Diseases of the heart and arterial system : Designed to be a practical presentation of the subject for the use of students and practitioners of medicine. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
46/888 page 22
![whenever it passes a point of constriction in its channel or flows suddenly into a portion of the containing-tube, Avhicli is wider than that directly above. These eddies and currents in their turn generate vibrations which are audible. These secondary currents are the fluid veins first demonstrated by Savart, but applied by Chauveau to the explanation of vascular and cardiac murmurs. Some of the conditions governing their production in the vas- cular system are the following: Constriction of the coats of a ves- sel by external pressure; projection into its lumen of calcareous plates or masses capable of turning the blood-stream from its direct course; aneurysmal sacs or vascular dilatations into which the blood-stream may swirl; and in the heart itself, all pathological changes by which orifices are narrowed and valves rendered in- competent. In addition, murnmrs can be produced by vibration of thin membranes and bands as the l)lood-current sweeps over them. In Virchow's Archives, Band cxl, is one of a series of sug- gestive papers, by Kichard Geigel, wherein he takes exception to the prevailing notion concerning the causation of endocardial and vascular bruits. By a series of nuithematical formula' Geigel en- deavours to prove that if murmurs of tlie })itch of those usually heard were produced by vibrations in the blood-stream these would have to be of a length that would be physically impossible within the cardiac cavities. He therefore states tliat the origin of bruits in eddies and currents is utterly impossible, and declares them due to transverse vibrations of the walls of the structures inclosing the blood-stream. His line of reasoning is ingenious, and to my mind has much to commend it, since the generally accepted theory is not altogether satisfactory. It is this consideration which makes me venture to dwell for a few numients on tlic ex])hinatiou of murmurs ofi^ered by David- son, of Edinljurgh. According to liis tlicory, murmurs are due to vibrations set up in the valves by the impact of the blood-stream at an oblique angle. By niuuerous experiments he claims to have demonstrated that when a stream of fluid was injected into a rubber balloon or a portion of the small intestine, one end of which was tied securely a})out the nozzle of tlic syringe while the other was tightly ligatured, tlu; fluid veins and eddies thus generated at the end of the nozzle witliin tlie elastic receptacle did not pro-](https://iiif.wellcomecollection.org/image/b21229533_0046.jp2/full/800%2C/0/default.jpg)
