. The mechanistic conception of life; biological essays. Life; Biology. 52 The Mechanistic Conception of Life the harbor at Kiel, when brought into the light and removed from the mud shows positive heliotropism. It is, therefore, just as incorrect to assert that the heliotropic reactions are governed by the bio- logical interests of the animal as that this is true for galvanotrop- ism. We must, there- fore, free ourselves at once from the over- valuation of natural selection and accept the consequences of Mendel's theory of heredity, according to which the animal is to be looked upon as an agg
. The mechanistic conception of life; biological essays. Life; Biology. 52 The Mechanistic Conception of Life the harbor at Kiel, when brought into the light and removed from the mud shows positive heliotropism. It is, therefore, just as incorrect to assert that the heliotropic reactions are governed by the bio- logical interests of the animal as that this is true for galvanotrop- ism. We must, there- fore, free ourselves at once from the over- valuation of natural selection and accept the consequences of Mendel's theory of heredity, according to which the animal is to be looked upon as an aggregate of in- dependent hereditary. Fig. 21.—Arrangement to prove that posi- tively heliotropic animals move toward the source of light even ii by so doing they go from the sun- light into the shade. IF PF is a window through which sunUght S falls into the room. By a piece of board d e the sunlight S is prevented from strUdng the region 6 c of a table near the window and this part of the table is in the shade. Only the daylight D can reach this part of the table. A test-tube a c is put on this table at right angles to the plane of the window. At the be- ginning of the experiment the animals (, the winged aphides) are all at o. The animals move at once toward the window, but instead of remain- ing at i> they keep on moving from the direct sunlight into the shade toward the source of hght until they all reach the end of the tube c near the window (in the shade) where they remain perma- nently. qualities. VII The attempt has been made to prove that organisms are attuned to a certain intensity of light and so regulate their heliotropism that they invariably reach that intensity of light which is best suited to their well-being. I believe that this is also a suggestion forced upon the investigators by the extreme application of the theory of natural selection. I have made experi- ments upon a large number of animals, but, with a clear. Please note that these images are extr
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