. Bulletin of the United States Fish Commission. Fisheries -- United States; Fish-culture -- United States. EXPERIMENTAL STUDY OF THE OYSTER GILL v^ which could not be attributed directly to changes in the surrounding medium. Excluding the cases of accidental mechanical stimulation that may cause the contrac- tion of the muscles in the gill tissue and result in a temporar}^ decrease in the velocity or even in a complete stoppage of the current, the range of the fluctuations observed in all the experiments varied with the temperature. It has been shown in a previous paper (Galtsoff, 1928) that
. Bulletin of the United States Fish Commission. Fisheries -- United States; Fish-culture -- United States. EXPERIMENTAL STUDY OF THE OYSTER GILL v^ which could not be attributed directly to changes in the surrounding medium. Excluding the cases of accidental mechanical stimulation that may cause the contrac- tion of the muscles in the gill tissue and result in a temporar}^ decrease in the velocity or even in a complete stoppage of the current, the range of the fluctuations observed in all the experiments varied with the temperature. It has been shown in a previous paper (Galtsoff, 1928) that between 15° and 25° the fluctuations are small, ranging from to per cent, but that they increase considerably both below and above these temperatures. This means that the nearer we approach the temperature limits of the ciliary activity the more irregular becomes the ciliary motion of the gills. It must be borne in mind that the flow of water from the gill cavity is due to the difference in pressure between the inside and the outside of the gills, and that. TtMPtRATURE;" C Fig. 5.—Effect of temperature on the rate o( flow oi water produced by the gills the velocity of the current is a function of a pressure drop between the two points. The head pressure inside the gill cavity is maintained by the activity of the lateral cilia and is dependent upon the rhythm and coordination of the ciliary motion along the whole surface of the gill. The beat of the ciliary cell has two distinct phases—a very rapid forward or effective stroke and a slow backward or regressive stroke. It has been shown by Weiss (1909) and Gellhorn (1925) that the work performed by the cilium during one phase is proportional to the cube of the velocity w=KV' . j,^,^^,i^i;:,(^, where Z is a constant, W is work, and V is velocity. The ability of the ciliated cells to transport particles or produce a current depends on the difference in the velocities. Please note that these images are extracted fr
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