70 FOOD OF THE VEGETATING PLANT. CHAP. U 



fifth, muriate of ammonia ; the sixth, acetate of lime ; 

 the seventh, sulphate of copper ; the eighth, crystal- 

 lized sugar; the tenth, vegetable extract. Plants 

 of Polygonum Persicaria and Bidens cannabina 

 were then immersed in each of these solutions with 

 the fpllowing result : In the solutions of muriate of 

 potass, muriate of soda, sulphate of soda, nitrate of 

 lime, and extract, the former species vegetated in 

 the shade for five weeks, developing their parts ; 

 but in the other solutions they died in the course 

 of a few days. The latter species succeeded or failed 

 in nearly the same way. It was afterwards found 

 that a portion of the salts had been taken up along 

 with the water by wfyich they were held in solution ; 

 and if we suppose the quantity contained in each of 

 the solutions to be divided into 100 parts, the ratio 

 of their absorption may be shown as follows : In 

 consuming one half of the water assigned to the ex- 

 periment, plants of the Polygonum had absorbed 14 

 parts of muriate of potass, 1 3 of muriate of soda, four of 

 nitrate of lime, J4 of sulphate of soda, 12 of muriate 

 of ammonia, eight of acetate of lime, 47 of sulphate of 

 copper, nine of gum, 2/ of sugar, and five of extract. 

 Plants of the Bidensh&d absorbed the several salts in 

 portions not very different.* But without minutely 

 regarding proportions, the fact is thus clearly ascer- 

 tained that plants are capable of taking up salts by 

 the root, at least when presented to them in a state 

 of artificial solution ; and if so, there is then reason to 



* Sur la Veg. chap. viii. sect. ii. 



