SCHULTZENSTEIN — NUTRITIVE CONSTITUENTS OF WATER. 131 



plant may be reckoned at from 1 J-2 lbs. daily ; so that when full- 

 grown it consumes mostly about 60 lbs. of water. It appears 

 that no physical drying takes place, from the fact that, as the 

 plant in autumn withers and decays, the evaporation diminishes 

 in an extraordinary degree. 



The very attenuated condition of the humous nutritive matter 

 in surface-water, makes an easy transmission of it possible. There 

 exist in surface-water, besides the humous extract, perhumate of 

 lime and ammonia, humates containing nitrogen, crenic acid and 

 its modifications, geic acid, humic acid, ulmic acid. Instead of 

 these acids there appear in the raw sap, after imbibition, gallic 

 acid, acetic acid, tartaric acid, malic acid, — also, instead of humous 

 extract, on the thickening of the raw sap, as for example in birch, 

 a gum which assumes the colour of a humic brown. These new 

 acids are slight modifications of the proportionate ingredients of 

 humic acid ; and it may be regarded as a proof that they arise from 

 these, that the colourless sap containing these acids is very easily 

 reduced through boiling to humus, of which it assumes the brown 

 tint. Carbonic acid and carbonate of ammonia are never found in 

 in raw sap. The further alterations are these : — the change of 

 mucilage (dextrine) in the sap into grape- and cane-sugar, as also 

 the separation, by respiration, of oxygen from the above-mentioned 

 vegetable acids, which are the only sources of the oxygen elimi- 

 nated from plants, whereby the plant assimilates not only carbon, 

 as in the carbonic-acid theory, but at the same time the hydrogen 

 and nitrogen of the base of the acids to form gum, sugar, wax, 

 fatty matter, starch, and wood. The easy transformation of 

 humus and of the bituminous constituents of the soil into gum 

 and sugar, appears from the extraordinary tendency of both, 

 especially in black soil, to form sugar in the cultivation of beet- 

 sugar and wine. The dark bituminous lime in the Crimea produces 

 a rich development of bunches and large berries ; the black clay, 

 early ripening and great sweetness. A large production of sugar, 

 from which wine acquires its peculiar strength, is found only in 

 dark clay and calcareous soil ; the vineyards on the light-coloured 

 Jura lime and white chalk yield a rich gathering, but a much 

 weaker wine. The darker the ground is with humus, the greater 

 is the quantity of sugar in the beet. Manuring with turf moul- 

 dering in the air has afforded the richest harvest of sugar-beet ; 

 the formation of sugar in beet is almost entirely prevented by 

 ammonia and fresh animal manure. 



The process of nutrition through the gradual transformation of 



k2 



