. The organism as a whole, from a physicochemical viewpoint. Biology; Mendel's law. Animal Instincts and Tropisms 275 from it. Thus the positively heliotropic animal would be compelled to move towards the source of light as a consequence of the fact that the intensity of the light increases the more the nearer the animal approaches the source of light. If the source of light be the reflected sky-light the dif- ference of intensity at both ends of a microscopic organ- ism is so slight that it is beneath the limit capable of influencing the motions. A simple experi- ment published by the writer
. The organism as a whole, from a physicochemical viewpoint. Biology; Mendel's law. Animal Instincts and Tropisms 275 from it. Thus the positively heliotropic animal would be compelled to move towards the source of light as a consequence of the fact that the intensity of the light increases the more the nearer the animal approaches the source of light. If the source of light be the reflected sky-light the dif- ference of intensity at both ends of a microscopic organ- ism is so slight that it is beneath the limit capable of influencing the motions. A simple experi- ment published by the writer in 1889 suffices to dispel the idea that the energy gradient determines the direction of the mo- tion of an animal in tropistic reactions. Let direct sunlight (S, Fig. 47) fall through the upper half of a window (w w) upon a table, and diffused daylight (D) through the lower half of the window on the same table. A test-tube a c is placed on the table in such a way that its long axis is at right angles to the plane of the window; and one half a b is in the direct sun-. Fig. 47. 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 Loeb, Jacques, 1859-1924. New York, London, Putnam's Sons
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbiology, bookyear1916
