ISBN: 9780217213356

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustra… Plus…

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1918 Excerpt: ... form a mental picture of what happened in this case, and they cut the knot by invoking a verbalism, namely by calling the making or breaking of a current a '' stimulus.'' This perhaps innocent verbalism then led to the less harmless dogma that only a rapid change could act as a stimulus.'' Thus Jennings253 and Mast346 took it for granted that phenomena of orientation by light could only be produced by rapid changes in the intensity of light and not by constant illumination, since they had the a priori conviction that only a rapid change in the intensity of a galvanic current or of light is a stimulus. The same difficulty arose in regard to the action of gravity upon orientation, since it was contrary to the definition of a stimulus that the mere permanent lying in a horizontal position should cause the apex of a stem to bend upward. All these difficulties disappear if we take the law of chemical mass action into consideration. Light acts not as a stimulus but acts by increasing the mass of certain chemical compounds, and it is the mass of these products which is responsible for the effect of light. Now, mass action is not proportional to the rapidity of the change of acting masses but to the acting mass itself. When two sides of an organism are struck by light of different intensity the quantity of photochemical products on both sides becomes unequal. In galvanotropism the galvanic current alters the distribution of the mass of certain ions along the nerve elements. It can be shown that gravitation acts by influencing the distribution of chemical substances in an organism. When the stem of a plant is put into a horizontal position certain chemical substances gather in greater concentration on the lower side of the st... Jacques Loeb, Books, Science and Nature, Forced Movements, Tropisms, And Animal Conduct Books>Science and Nature This is an OCR edition without illustrations or index. It may have numerous typos or missing text. However, purchasers can download a free scanned copy of the original rare book from GeneralBooksClub.com. You can also preview excerpts from the book there. Purchasers are also entitled to a free trial membership in the General Books Club where they can select from more than a million books without charge. Original Published by: J.B. Lippincott Company in 1918 in 224 pages; Subjects: Animal behavior; Tropisms; Animal orientation; Phototaxis; Animal mechanics; Animals; Juvenile Nonfiction / Animals / General; Nature / Animals; Science / Life Sciences / Biology / General; Science / Life Sciences / Zoology / General;<

ISBN: 0217213359

[EAN: 9780217213356], Neubuch, [PU: General Books LLC], BRAND NEW PRINT ON DEMAND., Forced Movements, Tropisms, and Animal Conduct (1918), Jacques Loeb