FACTS OF INHERITANCE 157 



that particular ancestral qualities may be latent 

 for more than two generations, and then re-assert 

 themselves as reversions ? What adjustment of 

 statement, if any, will bring Galton's Law (a 

 statistical conclusion) and MendeFs Law (an 

 experimental conclusion) into harmony ? What is 

 the nature of the character which we call " male- 

 ness " or " femaleness," and is there any law 

 which will formulate its distribution in the progeny 

 of a pair ? These are some of the urgent questions 

 towards the answering of which facts are accumu- 

 lating every month. 



The Transmission of Acquired Characters. — 

 Let us turn, however, for a little to the long-drawn- 

 out controversy as to the possible transmission of 

 " acquired characters," or somatic modifications. 

 It may be said that the disputants are now agreed 

 as to the precise point at issue, and perhaps it 

 may also be said that neither the yeas nor the nays 

 ring out so confidently as they did ten years ago. 

 Let us state the case. Members of the same species 

 often difier from one another, and these differences 

 can be measured and registered under the title of 

 " observed differences," which commits one to no 

 theory. Many of these differences depend on age 

 and sex, and these can be readily recognised and 

 allowed for. Others depend on peculiarities of 

 " nurture," in the wide sense ; that is, they are 

 the direct results of peculiarities in surrounding 

 influences or in function. Such changes in plant 

 or animal are impressed from without, they are 

 " exogenous " in origin, they are acquired not 

 inborn, and they are technically called " somatic 

 modifications," or " acquired characters." They 

 may be defined as structural changes in the body of 



