The Effect of Temperature on the Phototropic Response of Necturus
نویسنده
چکیده
I t is a well known fact that Necmrus maculosus is negatively phototropic. According to Eycleshymer (1906, 1908, and 1914) Reese (1906), and Pearse (1910), the animal always avoids sunlight in its natural environment as well as in the laboratory. They conclude that the skin is the important receptor for the photic stimulus since eyeless animals behave similarly to normal ones. I t is also known that Necturus is sensitive to temperatures below 5 ° and above 25°C. (Reese, 1906; Sayle, 1916). I have found that the animals become more active when transferred from a temperature of 20 ° to one of 2°C., but that after several hours of exposure to the low temperature, they become very sluggish. As the temperature increases they show increased activity until death ensues between 35 ° and 40°C. Violent spasmic movements are characteristic of such high temperatures previous to death. When illuminated, therefore, it may be assumed that the reaction time of Neaurus will vary according to the intensities of the thermal and photic stimuli. The experiments reported here were performed to determine the effect on the reaction time of variations of the temperature in normal and eyeless animals, and to express it in quantitative form. The animals were kept in a large aquarium with running water at 20°C. They were thus adapted to light of very low intensity and to a medium temperature. The animals were tested singly in a dark room, where the temperature and the light intensity could be easily controlled. They were placed in a rectangular blackened dish (170 cm. long, 11 cm. wide, and 8 cm. deep), and allowed 15 minutes for acclimatization. At the beginning of each trial, the animal was oriented in the center of the dish, with the longitudinal axes of the animal 569
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ورودعنوان ژورنال:
- The Journal of General Physiology
دوره 4 شماره
صفحات -
تاریخ انتشار 2003