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An Essay on the Forces which Circulate the Blood
An Essay on the Forces which Circulate the Blood Author:Charles Bell Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: of character to stop the bleeding from a principal artery ? What stuffing of clothes and 'pressing of one hand over the other! But what in truth is requisite to ... more »stop the pulsation in the most powerful artery ? textit{The pressure of the little finger is sufficient. See with what slight force the blood moves along the veins on the back of your hand. Yet slight as the pressure is which will stop the flow of that blood in those veins, and slight, consequently, as the impulse of the blood must be, the blood will make its way back to the heart, throwing down all the impediments which you have calculated upon, and open the heart itself. When Mr. Hunter laid bare the radial artery of a dog, and saw it contract, and, on cutting it across, saw the blood oozing only, and not flowing in a stream, he concluded that the obstruction of the blood was owing to the contraction of the artery. Can we agree tothis conclusion ? Before this experiment was made, did not the blood flow rapidly through the capillary extremities of that vessel some fifty times smaller than the trunk even in its contracted state ? Did the contraction of the artery bring it to the diameter of one of its own secondary or ternary branches ? If it did not, it could not be the smallness of the calibre that stopt the blood when the artery was divided. It was the injury from exposure, and the dissection, and the consequent attraction that began to prevail betwixt the vessel and the contained blood. In such a case there is blood contained within the vessel; but that blood is coagulated. I have examined the radial artery of a man cut across by a musket ball, when the blood stopt spontaneously ;. I found the blood coagulated for an inch in. the length of the artery. When vessels are divided in a wound, and the blood flows at...« less