AGRICULTURAL CHEMISTRY. 



moved from those in one field, while those 

 in the other field were left untouched. The 

 former produced 47 bolls, the latter only 37 

 bolls. 



These well-authenticated observations re- 

 move every doubt as to the part which sugar, 

 starch, and gum play in the developement of 

 plants; and it ceases to be enigmatical, why 

 these three substances exercise no influence 

 on the growth or process of nutrition of a 

 matured plant, when supplied to them as 

 food. 



The accumulation of starch in plants 

 during the autumn has been compared, al- 

 though certainly erroneously, to the fatten- 

 ing ot hibernating animals before their winter 

 sleep; but in these animals every vital func- 

 tion, except the process of respiration, is 

 suspended, and they only require, like a 

 lamp slowly burning, a substance rich in 

 carbon and hydrogen to support the pro- 

 cess of combustion in the lungs. On their 

 awaking from their torpor in the spring, the 

 fat has disappeared, but has not served as 

 nourishment. It has not caused the least 

 increase in any part of their body, neither 

 has it changed the quality of any of their 

 organs. With nutrition, properly so called, 

 the fat in these animals has not the least 

 connexion. 



The annual plants form and collect their 

 future nourishment in the same way as the 

 perennial ; they store it in their seeds in the 

 form of vegetable albumen, starch and gum, 

 which are used by the germs for the forma- 

 tion of their leaves and first radicle fibres. 

 The proper nutrition of the plants, their in- 

 crease in size, begins after these organs are 

 formed. 



Every germ and every bud of a perennial 

 plant is the engrafted embryo of a new indi- 

 vidual, while the nutriment accumulated in 

 the stem and roots, corresponds to the albu- 

 men of the seeds. 



Nutritive matters are, correctly speaking, 

 those substances which, when presented 

 from without, are capable of sustaining the 

 life and all the functions of an organism, by 

 furnishing to the different parts of plants the 

 materials for the production of their peculiar 

 constituents. 



In animals, the blood is the source of the 

 material of the muscles and nerves; by one 

 of its component parts, the blood supports 

 the process of respiration, by others, the 

 peculiar vital functions; every part of the 

 body is supplied with nourishment by it, 

 but its own production is a special function, 

 without which we could not conceive life 

 to continue. If we destroy the activity of 

 the organs which produce it, or if we inject 

 the blood of one animal into the veins of 

 another, at all events, if we carry this be- 

 yond certain limits, death is the consequence. 



If we could introduce into a tree woody 

 fibre in a state of solution, it would be the 

 same thing as placing a potato plant to 

 vegetate in a paste of starch. The office of 



the leaves is to form starch, woody fiore, 

 and sugar ; consequently, if we convey these 

 substances through the roots, the vital func 

 tions of the leaves must cease, and if the 

 process of assimilation cannot take anothe* 

 form, the plant must die. 



Other substances must be present in a 

 plant, besides the starch, sugar and gum, if 

 these are to take part in the developement 

 of the germ, leaves, and first radicle fibres. 

 There is no doubt that a grain of wheat con- 

 tains within itself the component parts of 

 the germ and of the radicle fibres, and, we 

 must suppose, exactly in the proportion ne- 

 cessary for their formation. These compo- 

 nent parts are starch and gluten; and it is 

 evident that neither of them alone, but ihat 

 both simultaneously assist in the formation 

 of the root, for they both suffer changes 

 under the action of air, moisture, and a suit 

 able temperature. 'The starch is convertel 

 into sugar, and the gluten also assumes a 

 new form, and both acquire the capability of" 

 being dissolved in water, and of thus being 

 conveyed to every part of the plant. Both 

 the starch and the gum are completely con- 

 sumed in the formation of the first part of 

 the roots and leaves; and excess of either 

 could not be used in the formation of leaves, 

 or in any other way. 



The conversion of starch into sugar during 

 the germination of grain is ascribed to a 

 vegetable principle called diastase, which is 

 generated during the act of commencing 

 germination. But this mode of transforma- 

 tion can also be effected by gluten, although 

 it requires a longer time. Seeds, which have 

 germinated, always contain much more dias- 

 tase than is necessary for the conversion of 

 their starch into sugar, for five parts by weight 

 of starch can be converted into sugar by one 

 part of malted barley. This excess of diastase 

 can by no means be regarded as accidental, 

 for, like the starch, it aids in the formation 

 of the first organs of the young plant, and 

 disappears with the sugar; diastase contains 

 nitrogen and furnishes the elements of ve- 

 getable albumen. 



Carbonic acid, water, and ammonia, are 

 the food of fully-developed plants ; starch, 

 sugar, and gum, serve, when accompanied 

 by an azotised substance, to sustain the em- 

 bryo, until its first organs of nutrition are 

 unfolded. The nutrition of a foetus and de- 

 velopement of an egg proceed in a totally 

 different manner from that of an animal 

 which is separated from its parent ; the ex- 

 clusion of air does not endanger the life of 

 the foetus, but would certainly cause the 

 death of the independent animal. In the 

 same manner, pure water is more advan- 

 tageous to the growth of a young plant, 

 than that containing carbonic acid, but after 

 a month the reverse is the case. 



The formation of sugar in maple-trees 

 does not take place in the roots, but in the 

 woody substance of the stem. The quantity 

 of sugar in the sap augments until it reaches 



