394 



SCIENCE 



[N. S. Vol. LIV. No. 1400 



Two persons whose brains are thus under de- 

 veloped may differ greatly in their mental 

 capacities, because they have fundamental 

 nervous differences, just as seedlings of differ- 

 ent species, while all alike under-developed, 

 differ in certain specific traits. Apparently 

 one group of hereditary mental defectives is 

 such because those who belong to it lack a 

 single factor for an adequate developmental 

 impulse. 



Epilepsy, of the ordinary juvenile, dement- 

 ing type, seems to be due, like feeble-minded- 

 ness, to a single developmental defect. Also, 

 dementia praecox has been found by several in- 

 vestigators to be due to a similar cause. 



But not only mental but also emotional 

 states have a hereditary basis. The prevail- 

 ing depressed mood appears to be due to a 

 glandular condition that is determined by a 

 certain developmental defect; and a prevailing 

 excitability appears to be determined by a 

 hereditary condition, which may be a tendency 

 to excessive secretion of the suprarenal glands. 



Moreover, the quality of our senses has a 

 clear hereditary basis, as the still unpublished 

 work of Dr. Hazel Stanton on musical families 

 clearly shows. It appears from these studies 

 that not only have great musicians an innate 

 capacity for discriminating between closely 

 similar qualities of pitch, intensity, time and 

 for tonal memory but they belong to families 

 with these innate capacities. Also, it has been 

 shown that these capacities are not improvable 

 by training ; they depend upon our very consti- 

 tution. Now we have evidence that persons 

 who have these capacities enjoy exercising 

 them. Those in whom the capacities are 

 slightly developed get no pleasure from exer- 

 cising them. We conclude that the reason why 

 musical people are such is primarily because 

 of their possession of inborn musical capaci- 

 ties. The musician is born, not made. From 

 these principles certain deductions seem natur- 

 ally to flow. A great color artist is one in 

 whom the innate capacity for color discrimi- 

 nation is well developed and his family shows 

 other examples of eolorists. The sculptor has 

 the hereditary capacity for form discrimina- 

 tion and that is why he finds his highest pleas- 



ure in the art. The author is one whose ver- 

 bal machinery is especially perfect. The sailor 

 is one who finds his greatest pleasure in the 

 beauty of form of the vessel, or perhaps in 

 broad horizons and distant lands ; he is neither 

 claustrophil, nor domestic. In general, our 

 vocations, or at least our avocations, are deter- 

 mined by our sensory structure and this is 

 hereditary. 



The fact that not only our physical but also 

 our mental and temperamental characteristics 

 have a hereditary basis has certain important 

 social bearings. It leads us to regard more 

 charitably the limitations- of our fellow men. 

 The false doctrines of human equality at birth 

 and of freedom of the will have determined 

 a line of practise in the fields of education and 

 criminology that, it seems to me, is not pro- 

 ductive of the best results. In education we 

 must know the child's native capacities before 

 we can properly train. In dealing with delin- 

 quents we must know the hereditary, mental 

 and emotional make-up before we can get an 

 explanation of the bad conduct and before we 

 can intelligently treat the delinquent. Organ- 

 ized society is too prone to " pass the buck " 

 of its own shortcomings to the hypothetical 

 " bad-will " of the offender against the mores. 

 We should do better if we treated the misde- 

 meanant as we treat a puppy whose actions 

 displease us. Either train him carefully, if 

 he is trainable; otherwise, put him in a posi- 

 tion where the exercise of his instincts will not 

 offend us. 



The relation of the glands of internal secre- 

 tion, commonly known as endocrine glands, to 

 human development and human behavior is be- 

 coming daily more obvious. Stature, build, 

 proportions; details of development of bone, 

 teeth, nails, hair, skin ; intelligence, emotional 

 control, all these things can be shown to be in- 

 fluenced by endocrine secretions. Indeed, it 

 seems naturally to follow that the hereditary 

 differences between people are due to heredi- 

 tary differences in the activity of these glands. 

 Now these glands, as is well known, secrete 

 substances called " hormones " which regulate 

 our physical, mental and temperamental con- 

 stitution. The special quality and quantity 



