520 EXPERIMENTS ON THE ROOTS OF PLANTS. 



but slightly coloured, containing but a very small proportion of the 

 gummy matter, no oily matter, and the aforesaid salts. I should be 

 led to believe that the exudation from the roots of these plants scarcely 

 tends farther than to reject the saline matter which is foreign to 

 vegetation. 



Chicoracea. — The plants examined were the Chrondrilla muralis 

 and the Sonchus oleraceus. They live very well in rain water ; the 

 latter acquires a clear yellow colour, a strong odour, and tastes bitter 

 and somewhat virous. It precipitates abundantly brown flakes of 

 neutral acetate of lead, and renders turbid a solution of gelatine. Eva- 

 porated slowly, the liquor, when concentrated, has a very strong and 

 persistent taste. The residuum of a reddish brown, by boiling absolute 

 alcohol, partly dissolves ; the alcohol evaporating leaves a yellow., 

 slightly brown, substance, of a very bitter taste, soluble in water, alco- 

 hol, and nitric acid, precipitated in brown flakes from its solutions by 

 nitrate of silver, and appears to be very analogous to the bitter prin- 

 ciple of the English chemists. The residuum, re-dissolved in water, has 

 a very strong virous taste, similar to that of opium; it contains tannin, 

 a brown gummy extractive substance, and some salts. 



Papaveracece. — Plants of the corn poppy (Papaver Rkceas) cannot 

 live in rain water ; they fade in it immediately. 



The white poppy (Papaver somniferum) will exist in it ; the roots 

 impart to the water a yellow colour; it acquires a virous odour, a bitter 

 taste, and the brownish residuum might be taken for opium. This 

 plant is one of those of which I cut the roots from the stalks, and 

 soaked them separately, and which imparted to the water none of the 

 properties which it acquired from the entire living plant. 



Euphorbiacece. — The plants tried were the Euphorbia Cyparisias 

 and E. Peplus. These are the euphorbias on which Brugmans says 

 he had observed the phenomenon of small drops oozing from the roots 

 during the night. Possibly I did not adopt the right method, as I 

 could not verify the fact by my own observations. The euphorbias 

 vegetate extremely well in rain water ; the liquor becomes slightly co- 

 loured, but acquires a strong and persistent taste, especially after it is 

 concentrated by evaporation. Boiling alcohol dissolves almost all the 

 residuum, which has but little colour, and by evaporation deposits a 

 granulous substance, gummy, resinous, yellowish, white, very acrid, 

 and unpleasant to the throat. 



Solanece. — The only plant of this family that I had time to vegetate 

 is the potato. It lived well in rain water, and developed its leaves* 



