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Between physiology and psychology there exists not only 

 an intimate correlation but an exact parallelism. The Brain 

 is the organ of the Mind, and thought but the result of 

 brain action ; and as the brain, as regards its size, structure, 

 and qualities is hereditarily transmissible, we are warranted 

 in asserting that every mental or intellectual state is 

 conditioned by a pre-existing physiological state and that 

 psychological heredity has its source in physiological here- 

 dity. Like all other groups of natural laws, physiology and 

 psychology are simply terms used to denote the groupings 

 of certain phenomena which experience has enabled us to 

 perceive are reducible to law. The physiological phenomena 

 concern unconsciousness, but inasmuch as every mental con- 

 dition implies and necessitates an antecedent physical 

 condition, there is of necessity an intimate correlation 

 between both. Thus the functions of the spinal cord, the 

 medulla oblongata, the cerebellum, are performed uncon- 

 sciously, and even the brain itself is capable of unconscious 

 cerebration. 



Proceeding from the unconscious towards the conscious, 

 we find that instincts, owing to the fact that the psychical as 

 well as the physical nature are unquestionab'y transmitted 

 from parents to their children, are hereditarily t ransmissible ; 

 so also are the modes of sensorial activity denominated the 

 perceptive faculties ; as every deficiency, and extraordinary 

 development of any of the senses are indubitably passed 

 on from parents to their offspring. To these latter must, 

 moreover, be added memory and imagination, which are 

 likewise potentially transmissible by heredity. Are the 

 higher, like the lower modes of intellect, transmissible ? As 

 the unity of the intellect is recognised and admitted by all 

 schools of thought, and as facts undoubtedly prove the 



