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October 13, 1900


JAMA. 1900;XXXV(15):953. doi:10.1001/jama.1900.02460410037006

The question of pain sensations in the lower animals is manifestly difficult to study. There are those who assume that movements or reactions to external stimuli in the lower animals are the outcome of psychical processes thereby induced. They at once assume the existence of the thing to be proved, namely, the existence of psychical processes in the organisms studied. According to this view, such forms as larval crustaceans, flies, the earthworm, the moth, etc., regulate their movements by consciousness. The moth, for instance, flies into the flame because of its curiosity to see more of the strange object.

Others seek to analyze the reactions of animals on mechanical grounds. Loeb shows that the orientation of lower animals with respect to light corresponds to the same phenomena in plants toward the same source of stimulus. Hence, plants must either be "conscious" or orientation of animals is explainable on mechanical grounds