The mechanistic conception of life : biological essays (1912)
Loeb, Jacques, 1859-1924 · Chicago, Ill. : University of Chicago Press · leaf 40
Mechanistic Conception of Life 29 heliotropic away from it), and the same is observed in motileanimals. In plants only the more refrangible rays from green toblue have these heliotropic effects, while the red and yellowrays are little or less effective; and the same is true for theheliotropic… … Fig. 20.—Positive heliotropism of a marine worm (Spirographis). (Fromnature.) The light fell into the aquarium from one side only and the worms allbent their heads toward the source of light, as the stems of positively heliotropicplants would do under the same conditions. constant; and the same…
