XI 



ECONOMIC 



A GENERALIZATION such as Mcndel's attracts two different 

 kinds of minds, the academic and the material. The 

 former seeks to develop and amplify the generalization, 

 inquires into the foundations upon which it rests, and 

 endeavours to discover not only the very nature of the 

 " materials " themselves but also the manner of their 

 production and transmission. The latter is less in- 

 terested in these " theoretical " problems, as he calls 

 them, but accepts the generalization with its formulae 

 and asks how they can be used towards an increased 

 production of material wealth. That the Mendelian 

 formulae can be so used is now no longer in doubt. 

 Pearl's and Nilsson-Ehle's results are proof sufficient. 

 That the latter did not identify the actual factors for 

 increased production and their individual effects may 

 be a disappointment to the extreme academic mind, 

 but the material mind is not to refuse Nilsson-Ehle's 

 highly productive varieties on that account. A new 

 and effective febrifuge or an antiseptic which acts upon 

 the internal tissues though applied on the surface is not 

 to be laid on one side till the physiologist or the bacterio- 

 logist discovers how it works. A child is not to be 

 prevented reading the face of the clock till it under- 

 stands the mechanism behind. 



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