142 



ot nitrogen is specially beneficiiil to the eereiiLs, but of little or no value to the 

 leguminosffl, especially af'er a cei'tain stage of their gi'owth. Without going into 

 the i-easons, or rather theories, which have been advanced to account for this state 

 of affairs, I will ask you to bear these facts in mind, and at the same time to remem- 

 ber that ex nihilo nihil fit, that we have to draw upon the soil, the air and water for 

 the constituents of plant food, and that llie soil, generall}' spcrdving, is the only one 

 of the three we can modify or alter in composition by mechanical or chemical agents. 

 The climate, including degree of frost, amount of rainfall, snow, sunshine, (fcc, all 

 these are important factors in agriculture. But as we have no control over the 

 elements the line of experiment seems rathei- in making choice of and breeding fiom 

 such varieties, whose qualities, dependent upon heredity and environment, make 

 them seem especially adapted to the climate immediately under consideration, and 

 then finding out, by all the means at our command, and applying those elemeuts 

 of plant food best suited to their growth and development. 



" In this series of expeiiments five well-known and hardy varieties of apple 

 trees were selected and the leaves gathered at two stages of their growth, viz., 25th 

 May and 20th September. The leaves in all ca>-es were taken from two or more 

 ti'ces, so that their analysis should reveal the fair average composition of the leaf of 

 that variety at that particular stage of the tree's growth. Upon the first date some 

 difficult}' was experienced in a few instances in getting sufficient leaves for analysis 

 without seriously denuding the ti-ee of foliage, so that these first specimens lepre- 

 sent leaves in a very early stage of development. On 2(lth September all the leaves 

 were still quite green, and their life apparently unimpaired and vigorous. 



" Mr. John Craig, Horticultui-ist to the Central Experimental Farm, has kindly 

 furnished me with the following descriptions of the aj^ple trees under discussion : — 



" Duchess of Oldenbitrgh. — Tjee is vigorous and hardy, forming a roundish, up- 

 right head. Bears young, and abundantly. Young shoots, smooth, reddish. Leaves 

 medium-sized, firm and glossy. September. 



" Tetofsky. — Tree upright, very haidy, vigorous. A young and annual bearei-. 

 Young shoots, stout, reddish-brown. Leaves very large. August. 



"Wealthy. — Hai d}^, vigf)rou8 and healthy. Spreading, open head. Bears young; 

 is an abundant and annual bearer. Shoots, dark, medium. Leaves medium, 

 October, 



" Fameuse. — Tree moderately vigoi-ous and hardy, round-topped, spreading. 

 Young shoots, reddish brown. Fairly young annual bearer. 



''Northern Spy. — Eapid, upright growth. Tardy und moderate bearer. Young 

 shoots, large, daik reddish-brown. Winter. 



" The following table shows the composition of the leaves, together with such 

 other data as may help to elucidate the question under consideration. Aft^^r the 

 column containing the name of the apple tree and the date when the leaves were 

 gathered are three columns, representing in percentages the composition of the 

 leaf — the water, organic matter and mineral constituents. Then follon' six columns, 

 showing the percentages of the chief inorganic components of the ash. The per- 

 centfiges- of nitrogen in the dry organic matter are then given, followed by columns 

 depiclitig the amounts of nitrogen, phos))hoiic acid and potash contained in 1.000 

 lbs. of the gj-een leaf, which serve to illustrate the absolute and relative values 

 of the leaves as a fertilizer, as well as to show the quantities of these materials taki-n 

 from the soil for the growth of the leaves. 



