IOO THE FEEBLY INHIBITED. 



VI. EVIDENCE FOR HEREDITY OF TEMPERAMENT DRAWN FROM 



STUDIES OF IDENTICAL TWINS. 



Since temperament is inherited, we can understand the cases, so 

 often cited, of similar mood in members of the same fraternity, and 

 especially in twins. Thus, Chatelain (1883) tells of twin sisters who 

 resemble each other to a striking degree and have lived together for 

 74 years. In 1872 one of them lost her husband. Both were seized 

 at the same time with the same form of melancholia, and recovered at 

 the same time. Last spring the husband of the second died, and the 

 same seizures occurred again. 



Gill (1883) describes twin sisters who were extremely alike in per- 

 sonal appearance, in manner, style, and speech, so that they were 

 easily mistaken for each other. They had similar illnesses at the same 

 time, even on one occasion when they were far apart and had not 

 communicated with each other. 



The sisters kept a lodging-house together. One, Mary, looked after 

 the domestic affairs; the other, Alice, was a milliner. Their two 

 brothers are feeble-minded and one has had an excited attack. An 

 elder sister has periodic depression and a younger sister is willful, 

 ungovernable. On November 20, 1879, Mary was admitted to the 

 hospital, restless and loquacious; then highly erotic in her delusions, 

 talking of men and marriage and alleging assault on the part of one 

 of her lodgers. Symptoms diminished until December 29, when excite- 

 ment increased, with violence, destructiveness, and increased delusions; 

 after January 5, 1880, Mary showed improvement; was flighty again 

 in May, and discharged recovered in October 1880. In December 

 1880 she was readmitted in a very depressed state, which was later 

 replaced by violence; she also had some sort of an unconscious spell. 

 She improved until November 1881, when she became very talkative 

 and liked to decorate herself ; was convalescent in March 1882; was 

 maniacal in July 1882, and has continued so until the time of reporting 

 in November 1882. 



Alice was admitted to the hospital on December 29, 1879, suffering 

 from exactly the same form of mental disorder as her sister ; has many 

 delusions of assault and persecution. She dressed fantastically, 

 laughed, sang, shouted, and acted erotically. In March 1880 the 

 patient was discharged recovered. On September 13, 1881, Alice was 

 readmitted with an attack of well-marked hysterical mania, the symp- 

 toms of which were very much like those of her first attack, only worse. 

 She improved until November 2 1 , when she again had a very mani- 

 acal attack, from which she began to recover, with short relapses, and 

 was discharged October 16, 1882. 



The nature of the two disturbances experienced by the sisters is thus 

 remarkably similar; but those of Alice had a shorter period. 



