. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CARBON MONOXIDE AND HEARTBEAT 37 reflection is totally eliminated. Except in very darkly pigmented individuals one can then clearly observe the heating heart. 3. Exposure of hearts to gases at elevated pressures A series of from four to six hearts was isolated and pinned to an elongate paraffin-coated tray of Lucite. Ringer's solution (Ephrussi and Beadle, 1936), containing phenylthiourea and streptomycin sulfate, was then added until each heart was covered by a film of the solution. In experiments with intact pupae the inse
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CARBON MONOXIDE AND HEARTBEAT 37 reflection is totally eliminated. Except in very darkly pigmented individuals one can then clearly observe the heating heart. 3. Exposure of hearts to gases at elevated pressures A series of from four to six hearts was isolated and pinned to an elongate paraffin-coated tray of Lucite. Ringer's solution (Ephrussi and Beadle, 1936), containing phenylthiourea and streptomycin sulfate, was then added until each heart was covered by a film of the solution. In experiments with intact pupae the insects were placed dorsal side up on a Lucite tray equipped with plastic cradles to ac- commodate the individual FIGURE 1. Apparatus for the exposure of pupae or of isolated hearts to flowing gas mixtures. The tray with either isolated hearts or intact pupae was then inserted into a Lucite chamber constructed to withstand high pressure (Schneiderman and Feder, 1954). The air-filled chamber was then sealed and compressed with carbon monoxide, the positive pressure being read from a gauge calibrated in pounds per square inch. The oxygen tension was therefore that of the initial air-filled chamber (21% atm.). In experiments utilizing oxygen pressures less than 21% atm., the chamber was first flushed with ten volumes of carbon monoxide. The system was then compressed with oxygen to a pre-determined pressure, making use of a mercury manometer. Finally, the chamber was further compressed with carbon monoxide. 4. Exposure of hearts to flowing mixtures of gases As shown in Figure 1, intact pupae were placed in linear sequence in the de- pression of an elongate, semi-cylindrical tray of cellulose acetate and slipped into 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 Marine Biological Laboratory
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
