. The Biological bulletin. Biology; Zoology; Marine biology. 436 MAHLON E. KRIEBEL 4th longitudinal muscle bands (Fig. 1), Such animals lived 3-5 days in sea water maintained at 10-20° C. Before the epicardiac membranes were severed, freeing the pericardium, small blood vessels in the interepicardiac septum were pinched with forceps to prevent bleeding. The pericardium was clamped between the arms of the V-shaped heart (Fig. 2), This method of holding the pericardium did not seem to impair the action of the heart, as blood continued to circulate for up to two days. Isolated hearts were prepare
. The Biological bulletin. Biology; Zoology; Marine biology. 436 MAHLON E. KRIEBEL 4th longitudinal muscle bands (Fig. 1), Such animals lived 3-5 days in sea water maintained at 10-20° C. Before the epicardiac membranes were severed, freeing the pericardium, small blood vessels in the interepicardiac septum were pinched with forceps to prevent bleeding. The pericardium was clamped between the arms of the V-shaped heart (Fig. 2), This method of holding the pericardium did not seem to impair the action of the heart, as blood continued to circulate for up to two days. Isolated hearts were prepared either by ligating and cutting the ventral and cardio-stomachic blood vessels or cannulating the vessels (Fig. 3). The cannulae. visceral reservoir valve"" - yTKl ^branchial "reservoir valve visceral reservoir 1 branchial reservoir 1 1 1 equalizing valve Figure 3. Cannulated heart. The valve arrangement permitted increases in water pressure in either arm of the heart. were connected to reservoirs filled with sea water to the same level as in the heart chamber. A valve arrangement permitted independent changes in applied pressure in each arm of the heart upon the raising or lowering of the reservoirs. Mechanical records of isolated hearts were made with a Grass FT-03 strain gauge positioned in line with each arm of the V-shaped heart (Fig. 4). Because the pericardium was clamped between the arms of the heart, tension resulting from contraction of one arm was not transmitted by the pericardium to the opposite arm. The two directions of contraction generally produced dif- ferent signals so the direction of contraction could be ascertained from the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectb, booksubjectzoology
