248 THE INDUCTIONS OF BIOLOGY. 



other cause can be ascribed the rapid metamorphoses under- 

 gone by the British races when placed in new conditions. It 

 is notorious that, in the United States, the descendants of the 

 immigrant Irish lose their Celtic aspect, and become Ameri- 

 canized. This cannot be ascribed to intermarriage with 

 Americans ; since the feeling with which Irish are regard- 

 ed by Americans, prevents any considerable amount of inter- 

 marriage. Equally marked is the case of the immigrant 

 Germans, who, though they keep themselves very much 

 apart, rapidly assume the prevailing type. To say that 

 " spontaneous variation ' increased by natural selection, can 

 have produced this effect, is going too far. Races so numer- 

 ous, cannot have been supplanted in the course of two or 

 three generations by varieties springing from them. Hence 

 there is no escape from the conclusion, that physical and so- 

 cial conditions have here wrought modifications of function 

 and structure, which offspring have inherited and increased. 

 Similarly with special cases. In the Cyclopcedia of Practical 

 Medicine, Vol. II. p. 419, Dr Brown states that he "has in 

 many instances observed in the case of individuals whose 

 complexion and general appearance has been modified by re- 

 sidence in hot climates, that children born to them subse- 

 quently to such residence, have resembled them rather in 

 their acquired than primary mien." 



Some special modifications of organs caused by special 

 changes in their functions, may also be noted. That large 

 hands are inherited by men and women whose ancestors 

 led laborious lives ; and that men and women whose descent, 

 for many generations, has been from those unused to manual 

 labour, commonly have small hands ; are established opinions. 

 It seems very unlikely that in the absence of any such con- 

 nexion, the size of the hand should thus have come to be 

 generally regarded as some index of extraction. That there 

 exists a like relation between habitual use of the feet and large- 

 ness of the feet, we have strong evidence in the customs of the 

 Chinese. The torturing practice of artificially arresting the 



