MULTIPLICITIES AND MALFORMATIONS 28^ 





generations of a human family. Bedart records quadruple 

 polydactylism of hands and feet through three generations of a 

 Perigord family (C. R. Soc. Biol. Paris, 9th series, vol. iv. 1892, 

 p. 367). Lucas cites a case of a Spanish family which included 

 forty instances of polydactylism, and Pliny tells of similarly dis- 

 tinguished families in ancient Rome. Hereditary polydact3'lism 

 is well known in cats. 



(c) Malformations of Parts. — There are records showing the 

 hereditary recurrence of abnormalities in dentition, in the eyes, 



Fig. 28. — Half-lop rabbit, an abnormal variation, which by artificial 

 selection has become a stable breed. (From Darwin.) 



in the hands (e.g. webbed fingers), in the feet (e.g. club-foot) 

 — indeed, in most parts of the body ; but in most cases the 

 likelihood of transmission does not seem to be great. 



(d) Pre-natal Influences resulting in Mutilations, Multipli- 

 cations, etc.— Recent embryological experiments have shown 

 incontestably that certain types of monstrosity can be readily 

 induced artificially by subjecting the developing ovum to shak- 

 ings, alterations of temperature, injections of various stuffs, 

 and so on ; and although the experiments relate mainly to birds, 



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