one doubts that particular instincts, aptitudes, and capacities are inherited among both animals and men nor that different races and species differ hereditarily in psychological characteristics. Certain breeds of dogs, such as the mastiff, the bulldog, the terrier, the collie, and many others, are characterized by peculiarities of temperament, affection, intelligence, and disposition. No one who has much studied the subject can doubt that different human races and families show characteristic differences in these same respects. It is quite futile to argue that exceptional individuals may be found in one race with the mental characteristics of another race; the same could be said of different races of dogs, or of the sizes of different species of beans or of paramecia. The fact is that racial characteristics are not determined by exceptional and extreme individuals but by the average or mean qualities of the race; and measured in this way there is no doubt that certain types of mind and disposition are characteristic of certain families.

There is no longer any question that some kinds of feeblemindedness, epilepsy, and insanity are inherited, and that there is often a hereditary basis for nervous and phlegmatic temperaments, for emotional, judicial, and calculating dispositions.

19. Body Build: Its Development and Inheritance [DAVENPORT, C. B., "Body Build and Its Inheritance," Eugenics Record Office Bulletin No. 24, February, 1925.]

The summary and conclusions of this study have been selected as follows:

Fleshy parents have, on the average, in our data, larger families than slender parents.

The offspring of two fleshy parents are twice as variable as those of slender parents.

There is a marked tendency for persons of similar build (or with potentialities for such) to intermarry. Dissimilar builds are selected against.

20. Inheritance of Stature

[DAVENPORT, C. B., "Inheritance of Stature," Eugenics Record Office Bulletin, No. 18, July, 1917.]

Dr. Davenport's summary and conclusions in part are as follows:

The offspring of two tall parents are less variable in stature than those of two short parents.

When both parents are "tall" or "very tall" and of tall stock, practically all the children are tall or very tall.

When both parents are "very short" or "short" and of short stock, all children are short or very short.

Short parents may, and frequently do, carry germ-cells which lack the shortening factors, while in tall parents the gametes are more nearly homogeneous and all lack most of the shortening factors.

There is evidence that the segments of stature are to a certain extent separately inheritable.

It is probable that in all forms of dwarfing there are multiple dominant inhibiting factors.

21. Mental and Nervous Symptoms

[CARNRICK, G. W. Co., Organotherapy in General Practice, pp. 231232. G. W. Carnrick Co., 1924.] (Adapted.)

Symptoms referable to the nervous system and defective mental development are of constant occurrence. In congenital cretinism and marked hypothyroidism in the young, definite structural change in the brain and central nervous axis are present. The normal functioning thyroid is indispensable for the development of normal mentality. In the marked condition of cretinism, typical "cretinic idiocy" is present. In lesser grades of subfunction, all gradations of mental retardation are encountered. While in total absence of the thyroid with idiocy there is brain structural defect, in the less advanced cases and those developing in childhood this probably does not exist, as these children can be restored to about normal mentality by thyroid therapy. Children are usually dull and stupid in the milder cases, and lack the spontaneity and interests of the normal child.

22. Heredity of Constitutional Mental Disorders [DAVENPORT, C. B., "Heredity of Constitutional Mental Disorders," Eugenics Record Office Bulletin No. 20, October, 1920, pp. 301-302, 304, 305-306.]

Very often the extreme lack of intelligence is associated with gross nervous and general developmental defects. . . . As a matter of statistics, the great mass of idiots arise from feebleminded parents.

The large number of pedigrees that have been collected by Goddard and by scores of students of feeble-minded children indicate that when both parents are mentally defective, all of

the children will be so also; that if neither of the parents is defective, but if they both have close relatives that are, then of their offspring only about one-quarter will show the defect; that when one of the parents is defective and the other not, but from a defective family, then only one-half of the offspring will be defective.

An analysis of over a hundred pedigrees of epileptics . . leads to the conclusion that the epileptic tendency is inherited as a simple Mendelian defect.

Dementia præcox, in which the dementing process seems to develop gradually . . . has a clear constitutional basis. . . . The method of inheritance of this condition has been investigated by various authors . . . and the conclusion seems supported that the tendency is inherited as a simple Mendelian recessive. That is, it follows the laws of inheritance that seem to hold for feeble-mindedness and common epilepsy.

In the field of temperament we have to do with matters of self-control . . . rather than of intellect. It is a matter of common observation that temperament and intellect are not closely related, and we have reason for believing that temperamental output depends upon the degree of functioning of internally secreting glands. . . . This trait is . . . apparently inherited as a Mendelian dominant.

23. Heredity and Environment in Mind Determination [KELLOGG, Vernon L., Mind and Heredity, pp. 101-108. Princeton, Princeton University Press, 1923.]

Nearly three tons of fresh thyroid gland tissue have to be used to get one ounce of thyroxin, the hormone secreted by the thyroid. But if there is too little thyroxin secreted into the blood by the thyroid gland of a child, the whole gland weighing hardly more than an ounce, that child may become a cretin with not only dreadful physical deformity but with the deformed and incomplete mind of an idiot. If there is a little too much the child may have a goiter, protruding eyeballs, a too rapid heart, and a restless, irritable brain. The pituitary gland weighs onesixtieth of an ounce, but if it is removed death ensues. If its secretions are too small in amount during childhood, growth is inhibited and a dwarf is produced. . . if too large in amount gianticism occurs often with accompanying imbecility.

With direct inheritance of mental capacity, with the inheritance of emotions and temperament, and with the inheritance

of differences in the functioning of the ductless glands whose secretions powerfully affect both emotions and intelligence, we have an imposing array of inherited factors in mental and nervous make-up.

24. The Endocrines

[WYNNE, Fred E., Ductless and Other Glands, pp. 50-69. New York, Alfred A. Knopf, 1923.]

The thyroid has been described as the "keystone of the endocrine arch" and it would be impossible to exaggerate the importance of its influence on the development and growth and the final make-up, physical, mental, and temperamental, of the individual.

It is evident, therefore, that the thyroid and its associated endocrine glands play an important part in the development of mind and character, and it is now generally admitted that within the limits of normal health there are slight preponderances of one or another set of glands which have a profound influence in determining the temperament and character of the individual.

Defective thymus activity may produce similar conditions in children. There is retardation of growth, often with flabby obesity, lethargy, and imperfect development of hair and nails.

25. The Endocrines

[BANDLER, S. Wyllis, The Endocrines, pp. 101-294. Philadelphia, W. B. Saunders Co., 1924.] (Adapted.)

Lack of secretion of the thyroid in infancy produces failure of growth and development both mental and physical. The thyroid is a necessary element in promoting growth in childhood and in controlling the development of body and mind. It rouses mental activity and is a cerebral stimulant.

I believe the anterior pituitary to be associated not only or always with strength of body, but decidedly with strength of mind. Its normal activities, so far as its trophic connection with the brain is concerned, lead to mental maturity, to judgment, to philosophy, to self-control. Under associated thyroid stimulation, an individual with such an anterior lobe would show wisdom, and in this class fall the wise, the elder statesmen.

The girl at school or college with a good thyroid and a good anterior pituitary is not only studious and bright but has a

more mature type of mind and is more settled than is the child with a good thyroid but a poor anterior pituitary.

26. Behavior and Gland Disease

[SCHLAPP, Max G., "Behavior and Gland Disease," Journal of Heredity, January, 1924, Vol. 15, pp. 3-17.]

"As a man thinketh in his heart, so is he," says the maxim. Since the Biblical proverb has already undergone considerable adaptation in achieving this wording and interpretation, it may not be unpardonable to revise it in conformity to recent science. Accordingly we may suggest, without disrespect, as a man functioneth in his neurones, so is he. .. Without pausing at this point to explain the inwardness of the matter, let me set down at once the fact that disorders of this functional activity of the cells in man are responsible for the existence of unnumbered individuals who are in greater or lesser degrees deranged from the normal, unable to adapt themselves to the environment in which they must live, misfits in this world of ours.

The contention is that many of these unhappy individuals are, with such exceptions as noted in my preceding article, the result of chemical disbalance in the blood of the mother. If, as I contended in my previous writing, the formative activity of the cells in the child may be disturbed by focal infections, the drain of infectious diseases, extrinsic poisons, such as narcotics, alcohol, and others, and particularly by gland disorders in the mother, these statements are also to be accepted in the case of functional disturbances. That is to say, outer and inner poisons and endocrine maladjustment in the female parent may not only cause cells of the child to grow badly, but in addition often lay the foundation for future functional disorders. Hence mental defectives of either formative or functional types frequently are the offspring of women suffering from slight or grave diseases of these all-important secretory glands. . .

For the physician and the parent, it is of the highest importance to note that such functional disturbances must be treated immediately upon their discovery, quite as in the case of formative troubles. Functional disorders of the ductless glands are progressive. Bad hormone balance irritates the nervous system, which in turn further upsets the glands, with the result that they proceed to function still more abnormally with added injury to the neuron groups. This vicious circle of disease causes all types of functional disorders to progress eventually to