AMERICAN INSTITUTE. 346 



gling for the same light one of them should be removed that the 

 other may attain full development, because in this way a less 

 aggregate amount of stem is required. Plants in destitute cir- 

 cumstances do not attain trunks, but remain shrubs. A greater 

 amount of leaf surface is exposed on a giv^n space by this arrange- 

 ment, yet, where the valuable products of an acre are a result — 

 as they are in most cultivated crops, of the full development of 

 the individual plants — this is to be secured, though at some ex- 

 pense. Thus an acre of thick grown carrots may give more 

 bushels of stunted product than an acre properly thinned; but 

 there will be a greater amount of worthless fibre in the plants. 

 Hence, where one fully grown plant can appropriate the sun- 

 shine, no attempt should be made to raise two; and the distribu- 

 tion of the plants of a growing crop should be such that at their 

 maximum development they shall completely cover the ground, 

 presenting a uniform mass of green leaf surface. 



The same principles apply to the amount of live stock a farmer 

 may find it profitable to keep on a given area. When one animal 

 can appropriate the food, any attempt to keep two will result in 

 loss, for both will become too feeble to render valuable products 

 of either growth or labor. In this way does a worthy theory run 

 like a guiding thread through the recesses of agricultural science. 



It is an error to undertake to discard all theories because none 

 of them are perfect. Only as science improves do we make any 

 progress in art. By a convenient hypothesis the child of the pre- 

 sent may comprehend what mighty men of the past attained only 

 through years of patient toil. To their crude notions, indeed to 

 their very errors, are we indebted for our present advanced posi- 

 tion, and the men of our day who lead the van of science, are 

 generally those who have made themselves most familiar with the 

 mighty intellects of the past, and with the difficulties and imper- 

 fections under which they labored while effecting progress. 



The best theories represent the aggregate wisdom of mankind. 

 To be without any theory, would be to live six thousand years ago. 

 The principal difference in the power of men arises from the more 

 or less comprehensive and complete character of their theories; 



