346 TRANSACTIONS OF THE 



they are the ideal out of wliicli man creates the actual world, and 

 after it is created classifies, comprehends and governs it. The 

 multiplicity of facts in agricultural or in any other science is now 

 so great as to be an incumbrance rather than resource, unless 

 arrayed by some theory. Like a mass of type in pi^ they must be 

 assorted and allotted before they can be used. 



The greatest and best of these forms not only include the 

 known but also reach forward into the unknown, and indicate the 

 direction in which future discoveries are to be made, so that when 

 what purports to be a newly discovered fact in nature controverts 

 approved theory, it takes a great amount of evidence to establish 

 it. It must not only prove itself, but it must remodel existing 

 theories to find a place. Thus, to prove a plant to grow without 

 air, or to prove the perpetual motion, would be to violate all 

 existing theories; and yet there are those, who, for want of the 

 elements of theoretical knowledge, spend their lives in the vain 

 attempt. To theories we owe that great conservative element in 

 public opinion which prevents too rapid fluctuations, as the latent 

 cold in ice prevents a general inundation with the first warm 

 days of spring. 



So unconsciously do men's theories mould their minds that 

 those who are loudest in the denunciation of all that is hypo- 

 thetical, are generally those wedded to some narrow and inchoate 

 notion for which they are the greatest sticklers. This is often the case 

 that a man can practice with no theory. Such a man takes his saw 

 and pruning knife and enters his orchard ostensibly without 

 theory; but if we follow him we shall find his ideal tree ?i fishing 

 rod. He is the most presumptuous innovator on nature, because 

 he understands least of her plans. Men must and will have some 

 theory. The fisherman who fashions a Grecian temple into a 

 hut, improves towards his notion of perfection. 



All honor then to the man who gives us the broadest and most 

 perfect theories; those which do most good. And equal, but no 

 greater honor to him, who, having the advantage of these theories, 

 overturns them by giving us better. Both deserve well of the 

 public. The work of both must become dilapidated, and fall to 

 pieces, in course of time, to furnish the material for newer and 

 more magnificent structures. 



