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aboral side acid action system activities Amoeba anode attached avoiding reaction bacteria bacterium become bend body carbon dioxide cathode cause ceases changes in behavior character chemical cilia collect contact reaction continues contraction course cyst depends determined direction of movement disk effect electric current Euglena experiments external conditions fact factors favorable flagella flatworm food reaction heat higher animals Hydra individuals induced infusoria injurious interference long axis lower organisms medusa ment Metazoa mouth move negative reaction objective observed occurs optimum oral side orientation oxygen Oxytricha Paramecia Paramecium pass peristome positive reaction produced protoplasm Protozoa pseudopodium react reaction to gravity reaction to light reflex region regulatory result reversal sea anemones sea urchin seen shown solid solution source of light species specimens spiral Stentor stimulating agent substances surface swarm spores swim backward swims forward temperature tentacles tion trial trichocysts tropism tube turning usually varied movements Vorticella
Página 336 - Paramecium in this behavior makes such an impression that one involuntarily recognizes it as a little subject acting in ways analogous to our own. Still stronger, perhaps, is this impression when observing an Amoeba obtaining food . . . The writer is thoroughly convinced, after long study of the behavior of this organism, that if...
Página 266 - The light operates, naturally, on the part of the animal which it reaches. The intensity of the light determines the sense of the response whether contractile or expansive, and the place of the response, the part of the body stimulated, determines the ultimate orientation of the animal.
Página 186 - We are neither of these, but simply investigators of earnest purpose and unbiassed mind, who study all things, prove all things, and hold fast to that which is good. We seek, inquire, reject nothing without cause, accept nothing without proof: we are students, not teachers.
Página 179 - The same individual does not always behave in the same Universality way under the same external conditions, but the behavior of tbl3 depends upon the physiological condition of the animal. The reaction to any given stimulus is modified by the past experience of the animal, and the modifications are regulatory, not haphazard in character. The phenomena are thus similar to those shown in the learning...
Página 266 - This orientation is produced, according to this tropism theory, by the direct action of the stimulating agent on the motor organs of that side of the body on which it impinges. A stimulus striking one side of the body causes the motor organs of that side to contract or extend or to move more or less strongly. This, of course, turns the body till the stimulus affects both sides equally; then there is no occasion for further turning and the animal is oriented" (JENNINGS 19063, p. 266). This is also...
Página 19 - We find that the simple naked mass of protoplasm reacts to all classes of stimuli to which higher animals react (if we consider auditory stimulation merely a special case of mechanical stimulation).
Página 291 - I behavior primarily characteristic for the second state comes to follow immediately upon the first state. The operations of this law are, of course, seen on a vast scale in higher organisms, in the phenomena which we commonly call memory, association, habit formation, and learning.
Página 289 - The changes toward which the physiological state tends are of two kinds. First the physiological state (like the idea) tends to produce movement. This movement often results in such a change of conditions as destroys the physiological state under consideration. But in case it does not, then the second tendency of the physiological state shows itself. It tends to resolve itself into another and different state.
Página 338 - ... JENNINGS. The results set forth in the preceding paper, together with certain other relations found in the behavior of lower organisms, that have been detailed in previous papers by the present writer, suggest a certain point of view in regard to the general method of regulation or adjustment in organisms. Everywhere in the study of life processes we meet the puzzle of regulation. Organisms do those things which advance their welfare. There are some exceptions, but this is certainly true in a...
Página 105 - Thereupon it pauses, swings its anterior end about in a circle, and finding that the water coming from one of the directions thus tried is not heated, it proceeds forward in that direction. This course leads it perhaps into the region of a fresh plant stem which has lately been crushed and has fallen into the water. The plant juice, oozing out, alters markedly the chemical constitution of the water.