FUNCTION OF THE NITROGENOUS MATTER OF SEEDS. 57 



the plants, were most carefully freed from ammonia. 

 The results of these experiments were as follows : In 

 an experiment where the plants were grown under a 

 glass bell, 4'780 grammes of seeds (lupines, beans, and 

 cresses), containing 0'227 gramme of nitrogen, gave 

 16*6 grammes of dried plants ; adding the amount of 

 nitrogen in the soil, 0*224 gramme ot that element was 

 recovered. In another experiment, where the plants 

 were grown in free atmospheric air, with the exclusion, 

 however, of dew and rain, 4*995 grammes of seeds (lu- 

 pines, beans, oats, wheat, and cresses) gave 18*73 

 grammes of dried plants. The seeds contained 0*2307 

 gramme of nitrogen ; the plants and soil, 0*2499 

 gramme. In the first series of experiments all ele- 

 ments of food were supplied to the plants, except nitro- 

 gen ; the chief conditions required to form unazotised 

 matter were given, but those required to form azotised 

 matter were altogether excluded. 



The growth of a wheat plant in pure water and at- 

 mospheric air is unattended with any increase of 

 weight. The normal seed-corn contains a certain quan- 

 tity of potash, magnesia, and lime, which are required 

 internally for the organic formative process ; but it has 

 no excess of those mineral substances that could serve 

 to effect the chemical process of a new production of 

 protoplasm. Where the mineral substances are ex- 

 cluded, the organs will absorb water, but neither car- 

 bonic acid nor ammonia ; at all events, these two latter 

 substances, even though they be introduced into the 

 plant by means of the water, exert no influence upon 

 the internal process ; they suffer no decomposition, and 

 no vegetable matter is formed from their elements. 



In Boussingault's experiments, the action of the 

 mineral substances supplied is unmistakable. The 

 weight of the plants produced was nearly 3^ times 

 greater than that of the seeds sown : but the quantity 

 of nitrogenous matter was the same as in the seeds. 

 Hence we have a clear production of non-nitrogenous 

 substance 2-J- times more than the original weight of 

 the seeds. A simple calculation" shows that the nitro- 



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