HEREDITY IN PHYSIOLOGY, IN MEDICINE, ETC. 335 



instance of the kind : A child had the odd trick of moving 

 his fingers rapidly about when pleased. When greatly ex- 

 cited he would raise both hands on either side of the face, 

 as high as the eyes, still shaking his fingers. After reaching 

 old age, he still found it troublesome to refrain from making 

 those gestures. He had eight children, one of them a lit- 

 tle girl, who from the age of four years had her father's 

 trick of shaking her fingers and lifting her hands. So, too, 

 heredity in handwriting has been noticed. There are fami- 

 lies in which left-handedness is hereditary. Various pecu- 

 liarities in the state of the organs of sense are transmitted 

 in like manner. Almost all the members of the Montmo- 

 rency family were affected with a slight squint, which was 

 called the Montmorency look. Inability to distinguish be- 

 tween different colors is well known to run in families ; the 

 famous English chemist Dalton, and two of his brothers, 

 were thus affected ; and hence the name of daltonism is 

 given to that peculiarity. Deafness and blindness are 

 sometimes hereditary, though rarely so ; the condition of 

 deaf-muteness still more rarely. Many strange instances 

 of the transmission of certain perversities of the sense of 

 taste are cited. Lucas relates, Zimmermann says, the fol- 

 lowing fact : In Scotland a man was haunted by an uncon- 

 querable longing to eat human flesh. He had a daughter. 

 Though separated from her father and mother, who were 

 sentenced to burning before she was a year old, and though 

 brought up among people in a good station of life, this 

 young girl gave way, like her father, to the incredible 

 craving for cannibalism. This instance clearly borders on 

 insanity. 



Insanity is assuredly transmitted by heredity. Esquirol 

 found among thirteen hundred and seventy-five cases of 

 madness three hundred and thirty-seven in which it was in- 

 herited. Guislain and other physicians calculate in a gen- 

 eral way that the number of cases of hereditary mental 



