NITROGEN, NITRIFICATION, NITROGENOUS MANURES 121 



In 1854 Boussingault again repeated his experiments 

 on nitrogen assimilation. This time he grew the plants 

 in a glass case so constructed that there was free 

 circulation of air from which all combined nitrogen had 

 been removed. These experiments were similar to his 

 second series, except the plants were not grown in a 

 limited volume of air. The results obtained showed 

 that the free nitrogen of the air, under the conditions of 

 the experiment, took no part in the food supply of the 

 plants. If anything, there was less nitrogen recovered in 

 the dwarfed plants than there was in the seed sown. 



128. Ville's Results. About the same time Ville 

 carried on a series of experiments of like nature, but in 

 a different way, and arrived at just the opposite con- 

 clusion. His experiments indicated that plants are 

 capable of making liberal use of the free nitrogen of 

 the air for food purposes. The directly opposite con- 

 clusions of Boussingault and Ville led to a great deal of 

 controversy. The French Academy of Science took up 

 the question, and appointed a commission to review the 

 work of Ville. The commission consisted of six promi- 

 nent scientists. They reported that " M. Ville's con- 

 clusions are consistent with his labor and results." 39 



129. Work of Lawes and Gilbert. A little later 

 Lawes and Gilbert carried on such extensive experi- 

 ments under a variety of conditions as to remove all 

 doubt regarding the plants' source of nitrogen. Plants 



