28 THE BEGINNINGS OF IIFE. 



plants ^. The most simple not-living or mineral con- 

 stituents coming into relation with one another in the 

 presence of preexisting protoplasm_, appear, for aught 

 we know to the contrary, to fall at once into those 

 subtle combinations which constitute the basis of living 

 protoplasm 2. The rapidity of the process mocks and 

 defies all theoretical explanation. Here, at all events, 



^ ' M. Boussingault has demonstrated that plants in full growth always 

 take carbon from the carbonic acid of the air, hydrogen from the water 

 which bathes them, and frequently azote from the air. . . . The soil he 

 used for the growth of his plants, the subjects of experiment, was a 

 siliceous sand, which was first sifted, then kept at a red heat for some 

 time, in order to destroy every trace of organic matter within it. It 

 was then moistened with distilled water, and the seeds sown ; after an 

 interval of a few days, the seeds which did not germinate were removed. 

 . . . Peas planted in a soil absolutely barren, and watered with pure 

 water, may attain to complete maturity, passing through all the phases 

 of their natural growth, and bearing flowers and ripe seeds. During this 

 process, they fix a large quantity of azote, which they must derive either 

 from the air dissolved in the water which they absorb by their roots, or 

 from the air that surrounds their stalks and leaves.' (' Chemical and 

 Physiolog. Balance of Organic Nature,' by Dumas and Boussingault, 

 Lond. 1844, pp. 76-90.) Whether the nitrogen is absorbed directly 

 from the air by the leaves, whether it passes into the plant as a con- 

 stituent of the air which is dissolved in the water taken up by the roots, 

 or whether it is derived from an infinitely small quantity of ammoniacal 

 vapour which constantly exists in the atmosphere, is a question which 

 cannot be considered as settled, though many probabilities point to the 

 latter source as that whence plants derive their nitrogen. 



2 Or else it may be that rearrangements are brought about amongst 

 the elements of the substances dissolved, and of the aqueous medium 

 itself, resulting primarily in the formation of colloidal combinations, 

 which secondarily (and under the continued influence of similar physical 

 forces) are capable of permitting the occurrence of new modes of col- 

 location resulting in the evolution of the minutest specks of living 

 matter. 



