The philosophy of the moving powers of the blood / by G. Calvert Holland.

Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: The philosophy of the moving powers of the blood / by G. Calvert Holland. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    ventricle would for some time be supplied with blood, were the contractions of the right to bo arrested. Tliis is not only a wise provision, tending to preserve existence under circumstances that would otherwise be fatal, but explains many interesting phenomena. It has just been remarked, that, in equal times, as much blood is sent out by the left side of the heart as is received by the right. This is true only in health, or when the functions of the limgs are regularly perfomied. A dispro- portion in tlie amount transmitted and received, must necessai'ily take place in all cases of recovery fi-om conges- tion of these organs. The idea of tliis disproportion occurred from the consideration of the following circum- stance :—Having observed the great difference in the capacity of the vente cavce, pulmonory ai'tery and aorta, it was natural to compare the pulmonary artery with the pulmonai-y veins. Knowing that these veins receive, in the same time, only as much blood as the artery transmits, though their conjoint capacity is greater, the question was suggested, what end is this greater capacity designed to serve ? The superiority of the venous system generally is obvi- ous and admitted. The pulmonary veins are alluded to by physiologists, as an exception to the prevailing prepon- derance. Their united capacity is regai-ded as only shghtly, if at all, superior to that of the pulmonary ai'tery. There is certainly some difficulty in making a compaiison, in consequence of the exti-eme shortness of the veins. An accurate investigation will not, however, estabhsh such rela- tion. Were direct evidence less decisive on this point, reasoning alone on the conditions of the blood, in these two classes of vessels, would render the opinion exceedingly questionable. The character of tlie stream emitted by the right ventricle differs very widely from that flowing through