PRACTICAL IMPORTANCE OF MEXDEL'S LAW 375 



expression in development, and through them ancestral con- 

 tributions may also find realisation (Galtonian inheritance). 



There should not, of course, be any opposition between Men- 

 delian and Galtonian formulae, for that is a confusion of thought, 

 to obviate which we have sharply separated the statistical from 

 the experimental study of inheritance. They are correlated, 

 and ultimately they will be seen in complete harmony, as different 

 aspects of the same phenomena. But it is simply muddle-headed- 

 ness which can find any opposition between a statistical formula 

 applicable to averages of successive generations breeding freely, 

 and a physiological formula applicable to particular sets of 

 cases where parents with contrasted dominant and recessive 

 characters are crossed and their hybrid offspring are inbred. 

 We may refer to the admirable essay by Darbishire (1906). 



§ 6. Practical Importance of Mendel's Discovery 



As Mendel's discovery is' extended it is bound to have a great 

 influence on the breeding of animals and the cultivation of 

 plants. Wherever it is applicable it will afford a solid basis 

 for action, enabling the breeder to reach his desired result more 

 surely, more rapidly, and more economically. The case we have 

 mentioned of the varieties of wheat susceptible and immune 

 to " rust " is in itself very suggestive. 



Possible Application to Mankind. — Although we do not yet 

 know of any reliable illustration of Mendelism in reference to 

 man, and although it does not apply in the familiar case of mu- 

 lattos, it would be rash to conclude that there is no application. 

 Search must be made for cases where two parents of well-marked 

 prepotent stocks differ from one another in sharply defined 

 unit characters. It must be remembered that intermarriages 

 between very different stocks are still common, and that crossing 

 of different races has been frequent in the past. 



When we think of Mendel's discovery in relation to our own 

 race, to which it may possibly apply, we see that its main idea 



