CHAPTER VIII. 



THE TRANSMISSION OF MALFORMATIONS AND ACQUIRED 

 DEFECTS. 



IN this chapter it is not proposed to discuss in all its 

 bearings the question of heredity, or even to propose a 

 theory to account for the transmission of defects from 

 parents to offspring. At the present day such an under- 

 taking is rendered unnecessary, for all thinking persons 

 are unanimous in believing that malformations of de- 

 velopment, as well as the tendency to certain diseases, 

 are inherited, or, as it is familiarly expressed, " run in 

 families." If anything, perhaps there is a disposition to 

 ascribe too much to inheritance instead of submitting 

 suspected cases to critical analysis. My object on the 

 present occasion is to criticize a few examples of sup- 

 posed instances of the transmission of characters the 

 result of mutilation. 



I shall commence with an easily observed part of a 

 mammal's body the ear, or pinna. In the chapter on 

 Environment it was pointed out that good evidence 

 leads us to believe that it is justifiable to regard the 

 pinna as an enlarged operculum, modified for acoustic 

 purposes in terrestrial mammals. Before discussing the 

 malformations of the external ear we may profitably 

 consider some facts connected with its anatomy. 



