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An eminent Bavarian botanist, Niigeli, has philosophised upon the subject 

 of universal sentience. " In the higher animals," he says, " sensation is 

 distinctly present in the movements consequent upon irritation. We 

 must therefore credit the lower animals with it as well, and we have no 

 reason to deny it in the case of plants and inorganic bodies." This claim 

 for continuity is attractive, but is much too sweeping, and not sufficiently 

 logical. No good purpose can be subserved by crediting minerals with 

 feeling, which we find Niigeli has done because their molecules exhibit 

 the attracting and repelling forces of chemical affinity. His assignment 

 of sensation to plants rests upon no better basis. Probably no author has 

 given more earnest attention and study to this subject than G. H. Lewes, 

 the distinguished English psychologist. He has told us, in his volume on 

 the object, scope and method in the study of psychology, that he was at 

 one time fascinated with the idea of a comparative psychology, which 

 should begin with simple organisms and thereby gain in strength of 

 interpretation upon reaching man. He began to collect materials 

 with this view, but afterward abandoned the project as impracticable. 

 We may parenthetically remark that his failure to secure material in 

 this way to interpret human action does not disprove the feasibility and 

 usefulness of a comparative psychology in which man shall receive only 

 the share of prominence due him as a member of the organic series. How- 

 ever, his studies made possible a far clearer insight into the distribution 

 of sensibility in organisms. One of his illustrations, very familiar to every 

 laboratory student, is especially pertinent. He says: " Touch the eye of 

 a frog, and there is at once the response of a reflex closure of the eyelid. 

 Touch the hairs of a Venus fly-trap {Dioncea muscipula), and there is at once 

 the response of a reflex closure of the leaf. Confine the frog and the 

 dioncea under a glass shade, and place there a sponge, over which ether 

 has been sprinkled. Both plant and animal breathe this air in which there 

 is vapor of ether, and as this vapor penetrates to their tissues we observe 

 a gradual cessation of all sensibility; first the reflex actions cease, then 

 the irritability of the particular tissues ceases. Stupor has supervened for 

 both. Now remove the glass shade; the vapor dissipates, the fresh air 

 penetrates to the tissues in exchange for the vitiated air, and both frog 

 and dioncea slowly recover their sensibility." From this experiment he 

 justly concludes "that the animal and plant organisms have with their 

 common structure common properties, and that if we call one of these 

 properties sensibility in the animal, we must call it thus in the plant." 

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