402 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 1913. 



lost all consciousness of their acts, epileptics for example, who in 

 their normal state have no recollection of what they may have done 

 during their frenzy, and also certain insane persons. There remains 

 for me the discussion of the inheritance of diseases, an interesting 

 phase of the question of heredity, because of its many practical and 

 important applications. We should distinguish, on the one hand, 

 betw^een inherited maladies, known as family diseases, which seem 

 to have no other cause than that of heredity, and, on the other hand, 

 the much more common illness where heredity plays only a predis- 

 posed or accessory part and is merely a factor among other more 

 active and more important agents. 



Charcot has described, under the name of " family maladies," cer- 

 tain affections of the nervous system; they habitually attack a con- 

 siderable proportion of the same family (25 or 50 per cent). They 

 take similar form and a like evolution with each of the stricken 

 subjects. They appear among these persons as the result of taint 

 originally from a germ, becoming manifest through their develop- 

 ment and independent of all exterior action. 



Since these first works of Charcot, the known number of diseases 

 wdth these characteristics has very much increased. Many family 

 affections are now known, not only of the nervous system but of all 

 organs of the body. These family maladies are transmitted in fami- 

 lies in the same manner as morphological characteristics ; they are 

 inherited under the same laws as malformation, such as the sixth 

 digit, already mentioned. As to malformations, they may pertain 

 more particularly to certain countries, certain races, and certain 

 groups of people, and especially to groups of people isolated by their 

 geographical locations or by their matrimonial customs. There is 

 nothing strange in the way that these malformations are manifest, 

 for they are the result of veritable inherited malformations. Thus, 

 there is a family disease called " I'atrophie papillaire f amiliale," and 

 which, with veiy few exceptions, attacks men only; the women of 

 these families are almost always exempt, and I will tell you to what 

 this happy privilege is due. The children of these families are born 

 normal and grow up full of health, but toward the age of 25 the 

 sight of some of them begins to weaken; if they consult an ophthal- 

 mologist he discovers, after exploring the depth of the eye, an atrophy 

 of the central bundles of the optic nerve and, in spite of all that can 

 be done, that wealmess progresses until there is almost a complete 

 loss of sight. One is led to believe that the disease comes from some 

 special physical defect — to an exaggerated narrowness of the cavity 

 where the optic nerve leaves the cranium. This cavity remains in a 

 fibro-cartilagenous condition during childhood; in men the ossifica- 

 tion of the circumference of the orifice is completed toward the age 

 of 25 ; but in women it more often remains incomplete. The malady 



