120 GENERAL FLUID COMPONENTS. [LECT. III. 



accurate examination of the proper juice of plants, 

 Mons. Chaptal found that in no two kinds of plants 

 does it agree as far as its sensible qualities are con- 

 sidered ; but as it is in the leaf that the change from 

 sap into the proper juice occurs, so its sensible 

 qualities are modified according to the action 

 which takes place in that organ ; and that this 

 should differ is not surprising if we consider the 

 great difference of the structure of leaves. In one 

 particular, however, Chaptal found that all the 

 specimens he examined agreed. When he poured 

 into them oxygenated muriatic acid, a very con- 

 siderable white precipitate fell down ; which had 

 the appearance of fine starch, when washed and 

 dried, and did not change when kept for a length 

 of time. It was insoluble in water, and was not af- 

 fected by alkalies. Two thirds of it were dissolved in 

 heated alcohol ; and these were evidently resinous, 

 as they were again precipitated from the spiritous 

 solvent by water. The third part, which continued 

 insoluble in both alcohol and water, was found 

 by Chaptal to possess all the properties of the 

 ligneous fibre. In the seed lobes a greater quan- 

 tity of this woody fibre was found than in the 

 proper juice of the plant itself; a fact which ac- 

 counts for the rapid growth and increase of parts 

 of the young plant, before the roots are able to 

 take up from the earth the principles of nutriment. 

 The proper juices of plants, both in the seed, and 



