THE INFLUENCES OF NURTURE 103 



years. The individual constitution was altered ; they 

 stopped shedding their leaves in autumn. Now, when 

 seeds of these false-evergreens, modification-evergreens, 

 were sown in certain mountainous districts with a con- 

 siderable amount of frost, they grew up into evergreen 

 peach trees. This looks at first sight like a demonstra- 

 tion of the transmission of an acquired character. But 

 one has to remember that a seed is a complex thing 

 with a considerable history behind it ; it is not a germ- 

 cell ; it is a young plant. The body of the seed had 

 probably been profoundly influenced by the body of 

 the parent plant before separation took place. So is 

 it in mammals and in Man. It is necessary to distinguish 

 between what is acquired or imprinted before birth and 

 what is in the strict sense part of the inheritance. 



There are many structural adaptations that almost 

 inevitably suggest to the impartial inquirer that they 

 have arisen by the cumulative inheritance of the results 

 of use and disuse or of peculiar environmental influence. 

 The camel and the wart-hog have great callous pads 

 which protect the skin on areas subjected to great pres- 

 sure. We know that callosities sometimes develop on 

 individual animals, as on our own hands, as the direct 

 result of pressure. What more natural than the inter- 

 pretation of the pads of camel and wart-hog as the result 

 of the hereditary accumulation of modifications ? What 

 more natural than to interpret in a similar way the 

 bUndness of cave animals or the shape of a snake ? 

 To this it may be answered that " what seems natural " 

 is not necessarily valid scientifically. Moreover, many 



