Chap. Vin. SALTS OF POTASSIUM. 179 



Potassium, Carhonate of (pure). — Half-minims of a solution 

 of one part to 437 of water were placed on six leaves. No 

 effect was produced in 24 hrs. ; but after 48 hrs. some of the 

 leaves had their tentacles, and one the blade, considerably 

 inflected. This, however, seemed the result of their being in- 

 jured ; for on the third day after the solution was given, three of 

 the leaves were dead, and one was very unhealthy ; the other 

 two were recovering, but with several of their tentacles appa- 

 rently injured, and these remained permanently inflected. It 

 is evident that the g^^ of a grain of this salt acts as a poison. 

 Three leaves were also immersed, each in thirty minims of a 

 solution of one part to 875 of water, though only for 9 hrs. ; and, 

 very differently from what occurs with the salts of soda, no 

 inflection ensued. 



Fotassium, Nitrate of. — Half-minims of a strong solution, of 

 one part to 109 of water (4 grs. to 1 oz.), were placed on the 

 discs of four leaves ; two were much injured, but no inflection 

 ensued. Eight leaves were treated in the same manner, with 

 drops of a weaker solution, of one part to 218 of water. After 

 50 hrs. there was no inflection, but two of the leaves seemed in- 

 jured. Five of these leaves were subsequently tested with drops 

 of milk and a solution of gelatine on their discs, and only one 

 became inflected; so that the solution of the nitrate of the 

 above strength, acting for 50 hrs., apparently had injured or 

 paralysed the leaves. Six leaves were then treated in the same 

 manner with a still weaker solution, of one part to 437 of water, 

 and these, after 48 hrs., were in no way affected, with the excep- 

 tion of perhaps a single leaf. Three leaves were next immersed 

 for 25 hrs., each in thirty minims of a solution of one part to 

 875 of water, and this produced no apparent effect. They were 

 then put into a solution of one part of carbonate of amnionia 

 to 218 of water ; the glands were immediately blackened, and 

 after 1 hr. there was some inflection, and the protoplasmic con- 

 tents of the cells became plainly aggregated. This shows that 

 the leaves had not been much injured by their immersion for 

 25 hrs. in the nitrate. 



Fotassium, Sulphate of. — Half-minims of a solution of one part 

 to 437 of water were placed on the discs of six leaves. After 

 20 hrs. 30 m. no effect was produced ; after an additional 24 hrs. 

 three remained quite unaffected ; two seemed injured, and the 

 sixth seemed almost dead with its tentacles inflected. Never- 

 theless, after two additional days, all six leaves recovered. The 

 immersion of three leaves for 24 hrs., each in thirty minims of 



