2. The old familiar classification of tempera ment recognizes the four types: sanguine, melancholic, choleric and phlegmatic. Both the choleric and the sanguine are supposed to be subject to rapid oscillations of emotional in terest, but with the sanguine individual, interest is rarely intense, whereas with the choleric it is rarely anything else. The melancholic and the phlegmatic represent the more persistent and dogged forms of interest but, like the previous pair, are distinguished by differences in the intensity of the interest, the phlegmatic person being less, the melancholic more, intense. These classifications are likely to be extensively i revised by current investigation.
3. The modern study of genius has not only contributed to a more definite conception of the nature of genius and the general mental char acteristics of the remarkable individual, but it has also revealed the hereditary character of marked intellectual superiority, and the rela tion between certain types of genius and mental defect.
Galton has gathered statistics to show that the frequency of genius is related in a definite and orderly way to the total number of persons in any given group. He has also shown that the genius appears with a background of hered ity which affords a reasonable explanation of his peculiar characteristics. The view often
urged by such writers as Lombroso that genius is essentially a morbid and degenerate mental phenomenon seems to be sound only in so far as concerns the liability of persons of remark able mental qualities to nervous derangement of various sorts. That insanity itself and genius are in any intrinsic sense identical is not generally granted. Among the interesting problems which deserve further study in the case of genius may be mentioned the deter mination of the extent to which the genius owes his superior endowment to heredity, as contrasted with education and favorable nurture; the ascertainment of the conditions which hinder or encourage the development of genius; the discovery of the general mental types to which the various remarkable individ uals conform.
Bibliography.— Binet and Henri, 'Annie Psychologique' (II, 1896, p. 411); Stern, der individuellen Differenzen' ; Galton, 'Hereditary Genius' ; Tarde, 'La Crimi nalite compare& ; Ellis, 'Man and (Studies in the Psychology of Thomp son, 'Mental Traits of Sex.'