40 THE CONTROL OF LIFE 



Btimuliis of a protective duty." '* The work done in 

 Denmark shows how the wealth of our country [Britain] 

 so far as it proceeds from dairy cattle might be nearly 

 doubled." These are but diagrammatic examples of the 

 kind of progress which the practical application of 

 Mendelian methods might immediately realise. 



We take another illustration from a lecture by Professor 

 William Bateson, one of the leaders of experimental 

 inquiry into the physiology of heredity and variation, 

 a study now spoken of as genetics. " No practical 

 dog-breeder or seedsman can see the results of Mendelian 

 recombination without perceiving that here is a bit of 

 knowledge he can immediately apply. No sociologist 

 can examine the pedigrees illustrating the simple descent 

 of a deformity or a congenital disease, and not see that 

 the new knowledge gives a solid basis for practical 

 action by which the composition of a race could be 

 modified if society so chose." And again : — " If we want 

 to raise mangels that will not turn to seed, or to breed a 

 cow that will give more milk in less time, or milk with 

 more butter and less water, we can turn to Genetics 

 with every hope that something can be done in these 

 laudable directions. But here I would plead what I 

 cannot but regard as a higher usefulness in our work. 

 Genetic inquiry aims at providing knowledge that may 

 bring, and I think will bring certainty into a region of 

 human affairs and concepts which might have been 

 supposed reserved for ages to be the domain of the 

 visionary." Professor Bateson here alludes to the change 

 of outlook that must follow the demonstration that this 



