112 QUARTERLY JOURNAL. 



with earth ; and this earth being weighed after the shrub or tre 

 had grown to maturity, and after taking out the tree, the dirt is 

 not found to have lost any of its weight. It thence follows that 

 the earth is only a bed to hold up the plant or the tree that it maj 

 receive its nourishment from some other source." 



Here will be seen at a glance the whole doctrine of atmospherii 

 food, which a certain class of physiologists contend for, and hav» 

 sought in modern times to establish by reference to the same ex 

 periment. But we must enter our unqualified protest against th< 

 doctrine as a whole, because — 



In the first place, we do not believe the experiment. The \\0i 

 which chemistry has lately thrown upon the structure and compel 

 sition of vegetables, makes the contrary too true to allow us t 

 believe any such thing. The fault lies in the way the experimer 

 has been tried, as can readily be shown. Thus — 



The ash left by burning dry oak wood with the dry leav 

 amounts to only 4.71 lbs. in 100. Now supposing the trees e: 

 perimented upon to contain the same proportion and to have bei 

 raised from the seed in the box, and there to have attained t] 

 weight of 5 lbs., then the quantity of ash left would be but 

 of a pound, which is all the inorganic matter that could ha 

 have been extracted from the soil, and being so small, would vc; 

 probably not be observed in weighing, especially when the diffe 

 ence in the moisture of the soil might have compensated for t! 

 whole loss. 



Again, if the soil serves only to keep the tree in an uprig 

 position, why will the tree not continue to thrive if cut off direct 

 above the roots and inserted in the soil, or merely propped up pe 

 pendicularly. Too much is now known of vegetable physioloj 

 to leave room for such theories. Plants draw nourishment frc 

 the air, but they draw equally important food from the soil. 



The practice of very many farmers at this day would seem 

 be built upon such a theory as that we have noticed. Althou; 

 the use of manures is well known, but probably not thorough 

 understood as regards the mode of their action, and though thi 

 application is insisted on by all rational farmers, yet raultituc 

 seem to view them as of little or no consequence, and suffer th( 

 to lie and waste unused. 



Such theories as this are, however, only the exceptions 



