194 MASSACnUSETTS HORTICULTURAL SOCIETY. 



quoted, b}' the horticulturist to wliom he made the remark, as fol- 

 lows : " While the question is not settled, I am inclined to the 

 opinion that, if nature in furnishing so al)un(lant a supply did not 

 give plants the abilit}' to use it, she is not so wise as she is 

 represented." While intelligent men think and talk in this way, 

 it is not out of place to discuss this ver}' important question, and 

 see what grounds there are for the doctrine to rest ui)on. If it is 

 wrong it is pernicious, as all wrong doctrines are, and it should 

 be exposed. 



These researches were carried out by all the parties on the same 

 general plan. The plants were grown in soils containing either no 

 nitrogen compounds at all, or a;ccuratel3' known quantilies ; so 

 that it could be determined at the end of the experiment just how 

 much nitrogen the crop had gained from that source. Taking 

 account of the fact that the atmospheric air always contains a small 

 quantity of nitrogen compounds, besides its large quantity of 

 uncombined nitrogen, the plants were supplied either with meas- 

 ured quantities of air, so that the possible amount of combined 

 nitrogen that they could get from that source could be estimated ; 

 or the}' were supplied with washed air from which all combined 

 nitrogen had been removed, so that they could get none at all 

 from that source. The amount of combined nitrogen in the seed 

 was determined by careful analysis of a sample of the kind of 

 seed planted. At the end of the experiment the whole quantity of 

 combined nitrogen in the products was no less careful!}' deter- 

 mined, hy the usual methods of chemical analysis. Evidently, 

 if the combined nitrogen in the products of the experiment 

 exceeded that in the soil, seed, and air from which the plant 

 could get its supplies of food, then free, uncombined nitro- 

 gen must have been forced into combination during the growth of 

 the plant. 



Boussingault's first experiments, in 1837, '38, and '39, were not 

 so carefully conducted as his later ones in 1851, '52, and '53 ; the 

 plants were grown in free air, but protected from the rain, from 

 which they might otherwise have obtained a considerable quantity 

 of coml)ined nitrogen. Clover appcnred to be able to gain nitro- 

 gen, over and above what was supplied to it, but oats gained 

 none. But, since the clover had access to a certain though 

 exceedingl}- small amount of combined nitrogen in the air with 

 which it was in free contact, there is no proof here, as Boussin- 



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