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germ cell. Nothing more marvellous in Nature than develop 

 ment of the germ cell. Relation of embryonic life to the parent 

 life. Darwin s theory of Pangenesis. Weismann s theory of 

 continuity of germ-plasm through successive generations. 

 Neither theory seems completely to account for the facts. 

 Darwin is strong in natural history ; Weismann in histology. 

 Mental life presents an entirely new problem in Heredity- 

 Can intellectual powers be traced to the germ-cell ? Close 

 resemblance between the embryos of animals and of man. 

 Can we account for hereditary transmission of mental char 

 acteristics ? Difficulty as to where, when, and how mental 

 phenomena first appear in individual history. How far the 

 vital relation between child and parents involves mental 

 inheritance. Embryonic life in its relations with mental life. 

 Knowledge an acquisition in individual history. Hence, evidence 

 for heredity in mind belongs mainly to the borderland, where 

 relations bodily and mental come together. Uncertainties still 

 cling to the mode, and to the extent, of mental variation 

 possible in this way. That there is a double problem in human 

 history must be admitted, and this admisssion must make 

 further demands on research, ...... 84-12] 



CHAPTEK VI 

 SENSORY AND RATIONAL DISCRIMINATION 



SENSORY discrimination belongs to all life ; rational discrimination 

 belongs to man only. Sensibility depends on the nerve system. 

 This varies in degree according to the complexity of the nerve 

 system. Movement is correlated with sensibility. Sensibility 

 and motor activity belong to the human organism, exactly as to 

 lower types of organic life. Need for a sharp distinction be 

 tween sensibility and rationality. Man interprets experience, 

 so as to obtain a knowledge of things. This is the distinction 

 of a rational life. The senses thus become instruments in the 

 service of a higher power. Rational life classifies acquired 

 knowledge, classifying objects according to distinct species. 

 This involves also discrimination of the facts of consciousness, 



