526 W. T. JAMES 



The relationship between these factors begins long before 

 the nervous system becomes the dominant influence in direct- 

 ing the actions of the body. The basis of the complicated 

 network of nervous centers and connecting fibers is estab- 

 lished early in the developing embryo. The refined differentia- 

 tions within the nervous tissue, although they have a genetic 

 basis, are dependent on the proper chemical balance of the 

 blood. This has been demonstrated in many cases in which 

 the endocrine glands have failed to react properly, resulting 

 not only in a deficient bodily structure but also in deficient 

 mental ability. A typical example of this is the retarded 

 development of the cretin, which is due to insufficient thyroid 

 secretion. If injections of thyroid material are given at an 

 early stage of development, the organism will continue its 

 growth processes, and normal bodily structure will result. 

 The deficiency of other glands, the pituitary, parathyroid, 

 testes, etc., also bring about physical deformities and be- 

 havior modifications. 



Although typical deficiencies may be shown for a specific 

 glandular abnormality, the normal action of the glands differs 

 for different constitutions. The action of a gland is related 

 to the genetic constitution of the particular organism, i.e., 

 the glandular secretion does not affect every organism in 

 the same manner. It has been shown that the patterning of 

 the genetic factors affects the relationship between glands 

 and form, and every other part of the organism is in turn 

 related to the pattern of these factors. The behavior, which 

 is dependent on nervous action in relation to every other 

 part of the body, is one vital part of this complex. Since 

 the organisms differ in form and glands, they should also 

 have significant behavioral differences. In fact it has been 

 recognized generally for centuries that the different physical 

 types among humans have characteristic psychological quali- 

 ties. It is due to this that so much attention has been given 

 in recent years to the constitutional reactions of different 

 types among humans. 



