. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. thrown upon quence of in- cold-blooded ts of the CAe- ittention, and to the general a recent com- Unce in other rays allow us ;, attention is ample of the of the reason- in facts: rhich the sub- ept under the :les, sinus. Y section, liga- itinue to beat, tlood. i tendency to ider pressure). i tendency to case with the to the hearts cold-blooded at may be re- -'cle. This is 1-hloo
. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. thrown upon quence of in- cold-blooded ts of the CAe- ittention, and to the general a recent com- Unce in other rays allow us ;, attention is ample of the of the reason- in facts: rhich the sub- ept under the :les, sinus. Y section, liga- itinue to beat, tlood. i tendency to ider pressure). i tendency to case with the to the hearts cold-blooded at may be re- -'cle. This is 1-hlooded ani- e (Octopus), a THE CIRCULATION OP THE BLOOD. 251 careful search has revealed no nerve-cells, yet their hearts con- tinue to beat when their nerves are severed, on section of parts of the organ, etc. 6. A strip of the muscle from the ventricle of the tortoise, when placed iu a moist chamber and a current of electricity passed through it for some hours, will commence to pulsate and continue to do so after the current has been withdrawn ; and this holds when the strip is whoU. free from nerve-cells. From the above facts certain inferences have been drawn: 1. It has been concluded that the sinus is the originator and director of the movements of the rest of the heart. 2. That this is owing to the ganglia in its walls. While all recognize the importance of the sinus, some physiologists hold to the gangli- onic influence as essentictl to the heart-beat still; while others, influenced by the facts mentioned above, are disposed to regard them as of very doubtful importance—at all events, as origina- tors of the movements of the heart. The tendency now seems to be to attach undue importance to the spontaneous contractility of the heart-muscle ; for it by no means follows logically that, because a muscle treated by electricity, when cut off from the usual nerve influence that we believe is being constantly exerted on the heart like other or- gans, will contract and continue
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Keywords: ., bookauthormillswes, bookcentury1800, bookdecade1890, bookyear1890
