100 HEREDITY IN RELATION TO EUGENICS 



Some extensive pedigrees of ataxy have been published. 

 One of the most extensive is by Mott (1905). It is repro- 

 duced in Fig. 65. 



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Fig. 64. — Part of Eichold-Flemino-Stosseit-Herzer pedigree showing 

 multiple sclerosis (black symbols). One notes the skipping of a generation 

 (indicating a recessive trait). The trouble is usually carried by unaffected 

 females (heavy circles) and appears in their sons. Interesting because same 

 family was independently noted by two neurologists. Pelizaeus, 1885; Merz- 



BACHER, 1909. 



Since, as the pedigrees show, normals may have affected 

 offspring the disease is probably dependent, as in insanity, 

 on the lack of something necessary for normal development. 

 The disease seems to be in no way sex-limited (Fig. 65). 



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Fig. 65. — Pedigree of a family with hereditary ataxy (black symbols). 

 Consorts not in direct line mostly unknown. Note that affected persons have 

 (for the most part) one affected parent; the trouble is due to the presence of 

 some positive character. Mott, 1905. 



The eugenic teaching is that affected persons and also 

 normals of the affected fraternities should marry only out- 

 side the strain. Whether all cases of atactic offspring of 

 one normal parent are derived from consanguineous mar- 

 riage is still uncertain and warrants hesitation in advising 

 the marriage of any atactic person. 



