. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. ar). TlMCloek-work klr over ihe cylinder tie mMrken ueieen A Mometer fails to express ed. innula is used, lel, the pressure into which it is vessel, of which pressure, in the i largely on the THE CIRCULATION OF THE BLOOD. S81 foroe of the heart-beat; consequently it would be expected, and it is actually found, that the pressure varies for different ani- mals, siie having, of cour
. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. ar). TlMCloek-work klr over ihe cylinder tie mMrken ueieen A Mometer fails to express ed. innula is used, lel, the pressure into which it is vessel, of which pressure, in the i largely on the THE CIRCULATION OF THE BLOOD. S81 foroe of the heart-beat; consequently it would be expected, and it is actually found, that the pressure varies for different ani- mals, siie having, of course, in most instances a relation to the result It has been estimated that in the carotid of the horse the arterial pressure is 150 to 800 mm. of mercury, of the dog 100 to 175, of the rabbit 50 to 9^" Man's blood-pressure is not Icnown, but is probably high, we may suppose not less than 150 to 200 mm. After the fact that there is a certain ccusiderable blood- pressure, the other most important one to notice is that this blood-pressure is constantly varying during the experiment, and, as we shall give reason to believe, in the normal animal; and to these variations and their oauaea we shall presently turn our attention. THE HEART. The heart, being one of the great centers of life, to speak figuratively, it demands an unusually close study. There is no special difSoulty in ascertaining the outlines of the heart by means of percussion on either the dead or the living subject. Quite otherwise is it with the changes in form which accompany cardiac action. Attempts have been made to ascertain the alterations in position of the heart with respect to other parts, and especially its own alterations in shape dur- ing a systole, the chest being unopened, by the use of needles thrust into its substance through the thoracic walls; but the re- sults have proved fallacious. Again, caste have been made of the heart after death, in a condition of moderate extension, prior to rigor tncrt
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Keywords: ., bookauthormillswes, bookcentury1800, bookdecade1890, bookyear1890
