INBORN AND ACQUIRED CHARACTERS 47 



embryo and foetus before actual birth. Thus the condition 

 of a child at birth may have been influenced by the con- 

 dition under which the mother has lived during pregnancy. 



The offspring always varies from its parent, often in 

 many ways. It may vary in size under similar conditions 

 of nourishment and environment ; it may vary in colour, 

 hairiness, shape of features, and in a hundred other points. 

 These differences are inborn and are known as variations. 

 Variation is a common property of living matter, and will 

 be dealt with more fully later. 1 At present it is sufficient to 

 refer to it thus briefly. The new individual then inherits 

 the bulk of its inborn characters from its parents, but pos- 

 sesses some new inborn characters of its own in the form of 

 variations. 



Acquired characters are, as has already been said, those 

 characters that are due to the action of various stimuli upon 

 the organism from the time it commences its existence as a 

 fertilised ovum. But these characters could not appear 

 unless the potentiality of producing them were present in 

 the fertilised ovum and in the cells derived from it. The 

 potentiality of producing a character of reacting in a par- 

 ticular manner to a particular stimulus is itself an inborn 

 character; therefore acquired characters must be regarded 

 as modifications of inborn characters produced by external 

 stimuli. This does not mean that acquired characters are 

 inborn in themselves, but simply that the potentiality of 

 making an acquirement is inborn. We will take the clas- 

 sical example of a scar. The father may have a particular 

 shaped scar on his nose, which has been produced by an 

 injury during some period of his life. His nose may be of a 

 characteristic shape. It is quite likely that the child may 

 inherit the peculiar shape of his nose, but it is certain that 

 the child will not inherit the scar. The child will, however, 

 inherit the potentiality of reacting to injury in the same way 

 as his parent reacted ; thus when a certain portion of tissue 

 is destroyed or distorted by injury, the cells will react to the. 



1 See p. 59. 



