THE BIOLOGY OF SOIL. 67 



peculiar mechanism of the organism concerned, and 

 cannot hope to attain success without experiment- 

 ing with it. I confess it seems to me as reasonable 

 to look upon scientific agriculture as a branch 

 chiefly of chemistry as it would be to look upon 

 horse-breeding or pigeon-rearing from the same 

 point of view ; and why the professed chemist's 

 advice is regarded as so comforting and final in 

 the one case and not in the other is one of those 

 mysteries which seem inherent in human nature. 



The central point in agriculture is the plant : 

 get the most out of it the energy- winning 

 machine which alone can keep the animals and 

 everything else connected with the farm going 

 and all the rest follows. The old agriculture has 

 taken a gloomy view of things, and especially on 

 account of a large variable which it blames for 

 many ills, namely, the season or climate. Perhaps 

 the old agriculture has not sufficiently recognised 

 that Nature grows plants in accordance with the 

 fact that variation is not peculiar to the weather : 

 if the seasons vary, so do fruit and other produce 

 and the plants which yield them ; and since man 

 cannot hope to control the one variable, possibly 

 relief will be found in doing more, within his 

 limits, towards controlling others. 



In any case he cannot hope to succeed without 

 study of the physiology of the plant. 



Notes to Chapter VIL 



An admirable short account of soil in its relation to root- 

 hairs is given in Sa.chs' Lectures, XV. ; but for a more exhaustive 



