American journal of physiology . teries would be visible in the pressure-curve, provided it werewritten with a sensitive manometer. The heart of a dog anaesthetized with ether was exposed, theramus descendens of the left coronary artery ligated about two centi-metres from its origin, and a cannula tied into the central end. The 1 Martin, H. N., and W. T, Sedgwick: Journal of physiology, 1882, 165. 152 W. T. Porter. cannula was then connected by thick-walled but flexible rubber tubingto a glass tube, which led to a sensitive Hlirthle membrane manom-eter, placed on the level of the artery
American journal of physiology . teries would be visible in the pressure-curve, provided it werewritten with a sensitive manometer. The heart of a dog anaesthetized with ether was exposed, theramus descendens of the left coronary artery ligated about two centi-metres from its origin, and a cannula tied into the central end. The 1 Martin, H. N., and W. T, Sedgwick: Journal of physiology, 1882, 165. 152 W. T. Porter. cannula was then connected by thick-walled but flexible rubber tubingto a glass tube, which led to a sensitive Hlirthle membrane manom-eter, placed on the level of the artery. Evidently a manometer thussituated must receive the pressure-changes in the ramus circumflexusof the left coronary artery and in the branches given off by the ramusdescendens in the first part of its course, /. c, between its origin andthe cannula. A second manometer recorded simultaneously thechanges of pressure in the carotid artery. But the hope of securinga curve from the coronary arteries differing from the pressure-curve. Fig. 3. Sept. 16, 1895. Curves of the blood-pressure in the left coronary artery (uppertracing) and the carotid artery (lower tracing) of the dog, recorded half the original size. The horizontal line below each curve is the line ofatmospheric pressure. In the case of the carotid artery, the atmospheric pressureline served also for the record of the time, in fifths of a second. The intervals of thegraduation-scales correspond to a pressure of 20 mm. Hg. On raising the pressure inthe Hiirthle manometers to 100 mm. Hg, as here recorded, and then opening thechamber of the manometer to the pressure of the atmosphere, the writing points re-turned accurately to the line of atmospheric pressure, — this line in the pressure-scalebeing thus twice drawn. The vertical lines are synchronous ordinates. During thelatter part of the curves, the heart was slowed by vagus excitation. of Other arteries was not realized. The most careful scrutiny of t
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