48 



fertile." Here we have the experience of antiquity agreeing with the 

 practice of the modern intelligent farmer who ploughs clover into the 

 ground in order to obtain a good crop of wheat. 



From 1863, experiments and disputations on the question again 

 ceased until 1881, when an intelligent land owner in North Germany, 

 named Schultz, published his experiences in farming, and awakened the 

 attention of the agricultural world of Europe. Both practical farmers 

 and scientific agriculturists are now fully agreed that the fixation 

 of nitrogen by leguminous plants is a reality. The most decided 

 pronouncements ever made on the subject were delivered at 

 Halle, in January, in 1891, at the 64th meeting of German 

 investigators and physicians. Prominent among those were Maercker, 

 Wagner and Hellriegel, but American and English authorities were also 

 present including Atwater, Lawes and Gilbert. The last named gentle- 

 man, Sir Henry Gilbert, who visited Canada a few months ago, gave a 

 discourse on the fixation of free nitrogen from atmospheric air by 

 plants. He had presided in 1886 at Berlin, when Hellriegel gave the 

 results of his first investigations regarding the question of nitrogen and 

 the leguminosoe. Previously, in 1884, Hellriegel had brought the 

 formation of the little bulbs on the roots into connection with the fixation 

 of nitrogen. Sir Henry Gilbert told his audience that at Rothamsted, since 

 1 888, elaborated trials on this subject had been carried on, the characters of 

 which were illustrated photographically. Those experiments entirely 

 confirmed Hellriegel's results. They shewed that peas, vetches, lupins, 

 lucerne, white and red clover, are all capable of directly assimilating 

 nitrogen, although in different measure. The lecturer discussed 

 minutely the nature and action of the tubercles, without however 

 coming to very decided results as regards their mode of activity. Some 

 of them are as large as walnuts, and the investigators are still inclined 

 to believe that the bacteria they contain are instrumental in digesting 

 the nitrogen. Hellriegel was of opinion that the study of these tubercles 

 was far from ended, and would occupy them a long time yet. He 

 stated that peas are unable to appropriate either nitric acid or ammonia 

 from the soil ; that lupins cannot thrive when supplied with nitrate of 

 lime, but perhaps with nitrate of ammonia. Meyer was glad to be able 

 to observe that although Hellriegel's investigations had overtaken and 



