100 STUDIES OF PHOTO-SYNTHESIS 



upon the wrong side. Eminent men, supporting error unconsciously 

 with negative experiments, have stated that the nitrogen was 

 obtained from the soil and never by the leaves from the air; less 

 known men, backing their statements by positive proofs, were on 

 the other side, but the eminence and authority of their rivals was 

 too much for them, and so it comes about that in this matter we 

 still almost universally believe and teach " the thing that is not." 



It was Priestley himself, the discoverer of the like process for 

 carbon assimilation, who in 1771 first asserted that plants were able 

 to absorb the nitrogen of the air, and Ingenhousz shortly after 

 endorsed this statement. But this earlier view was contradicted, 

 first by de Saussure, and later by Woodhouse, Senebier, and then 

 by the eminent agricultural chemist Boussingault, in France, and 

 the no less eminent Lawes, in England. 



Ville, in France, stoutly maintained that plants absorb nitrogen 

 from the air, and his findings were confirmed by a specially appointed 

 Committee of the Academic des Sciences. Boussingault repeated 

 his own experiments with the utmost care and every precaution, 

 and again obtained negative results. This was later confirmed in 

 an elaborate series of researches made by Lawes at Rothamsted; 

 and the eminence and great authority of these two distinguished 

 men settled the controversy in their favour for a generation. 



Experiments that we have ourselves made in the course of the 

 present investigation, as to the growth of the seeds of higher plants 

 (mono- and di-cotyledons) in sand and water cultures, upon media 

 free from compounds of nitrogen, have convinced us that the 

 experimental results of these observers were correct, but their 

 deductions profoundly erroneous. The seedlings we obtained were 

 dwarfs, although they flowered and seeded, and they assimilated 

 scarcely any nitrogen. This does not by any means settle the 

 problem ; it only proves that, so far as the higher plants are con- 

 cerned, this is an abortive method of experimentation. If the con- 

 ditions of environment are such as to make any feeble growth 

 pathological, and if the dry weight of the plant scarcely exceeds that 

 of the seed from which it grew, it is scarcely to be expected that 

 there should be an increase in nitrogen. On the other hand, had the 

 seeds grown into anything like normal plants, it would have been 

 an unthinkable monstrosity in nature that carbon, hydrogen, and 

 oxygen should go up without any accompanying increase in the 

 nitrogen. 



