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the air, either directly or indirectly, by means of minute organisms 

 now generally termed microbes. These microbes can be connnuni- 

 cated by direct inoculation from one plant to another that has been 

 previously free from them. Experiments are in progress as to the 

 possibility of cultivating these microbes artificially, and when this 

 has been accomplished successfully it will mark a great step toward 

 the solution of the question as to the plant's method of obtaining 

 nitrogen, and not only that, but a great step toward success in agri- 

 culture, since every one will be able to inoculate his own plants, and 

 thus immensely stimulate the yield of crops. 



T. Leone has shown that a great number of germs obtain their- 

 nitrogen more easily by decomposing the nitrates, and only when 

 these salts are used up do they begin to nitrify the ammoniacal com- 

 pounds, and after that possibly attack the free nitrogen of the air. 

 He has also shown that these take the nitrogen as a gas from the 

 nitric acid in the nitrates and do not convert it into ammonia. ( Agr. 

 Sci., Vol. V, p. 82.) 



Leone also shows that the phenomena of nitrification and denitri- 

 fication occur alternately according to the relative amount of nutri- 

 ment and number of bacteria present in the water. The manuring of 

 soil, therefore, gives rise to a cycle of phenomena, nitrification being 

 first arrested and the nitrates and nitrites reduced until a maximum 

 formation of ammonia is attained, when nitrification again com- 

 mences. The destruction of the nitrates and nitrites in the soil is 

 complete or partial according as the supply of manure is abundant 

 or otherwise. (Agr. Sci., Vol. V, p. 107.) 



The experiments made in Europe by Boussingault, Hellriegel, and 

 others as to the method by which plants obtain the nitrogen from the 

 atmosphere have been repeated and extended by C. D, Woods, of the 

 Storrs School Agricultural Experiment Station. His results are 

 summarized as follows: 



(1) Peas, alfalfa, serradella, lupine, probabl}^ clover, and appar- 

 ently all leguminous plants, have the power of acquiring large quanti- 

 ties of nitrogen directly from the air during their growth. There 

 is no doubt that the free nitrogen of the air is thus acquired by these 

 plants. This acquisition has something to do with the tubercles on 

 the roots of these plants, but the details of the process are still to be 

 solved. The cereals, oats, etc., with which experiments have been 

 brought to completion, do not have this power of acquiring nitrogen 

 from the air, nor do they have such tubercles as are formed on the roots 

 of the legumes. They get their nitrogen from the nitrates or nitrogen- 

 ous fertilizers. The tubercles on the roots of the legumes may 1 )e formed 

 either after or entirely without the addition of solutions or infusions 

 containing micro-organisms, and a ijlausible supposition is that vrhen 

 such infusions are not furnished the spores of the organisms were 



