Chap. VIII.] SALTS OP POTASSIUM. 147 



remained quite unaffected; two seemed injured, and the sixth 

 seemed almost dead, with its tentacles inflected. Nevertheless, 

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

 of three leaves for 24 hi-s., each in thirty minims of a solution of 

 one part to 875 of water, produced no apparent eflFect. They were 

 then treated with the same solution of carbonate of ammonia, 

 with the same result as in the case of the nitrate of potash. 



Potassium, Phosphate of. Half-minims of a solution of one 

 part to 437 of water were placed on the discs of six leaves, which 

 were observed during three days; but no effect was produced. 

 The partial drying up of the fluid on the disc slightly drew to- 

 gether the tentacles on it, as often occurs in experiments of this 

 kind. The leaves on the third day appeared quite healthy. 



Potassium, Citrate of. Half-minims of a solution of one part 

 to 437 of water, left on the discs of six leaves for three days, and 

 the immersion of three leaves for 9 hrs., each in 30 minims of a 

 solution of one part to 875 of water, did not produce the least 

 effect. 



Potassium, Oxalate of. Half-minims were placed on different 

 occasions on the discs of seventeen leaves; and the results per- 

 plexed me much, as they still do. Inflection supervened very 

 slowly. After 24 hrs. four leaves out of the seventeen were well 

 inflected, together with the blades of two; six were slightly af- 

 fected, and seven not at all. Three leaves of one lot were ob- 

 served for five days, and all died; but in another lot of six all 

 excepting one looked healthy after four days. Three leaves were 

 immersed during 9 hrs., each in 30 minims of a solution of one 

 part to 875 of water, and were not in the least affected; but they 

 ought to have been observed for a longer time. 



Potassium, Chloride of. Neither half-minims of a solution of 

 one part to 437 of water, left on the discs of six leaves for three 

 days, nor the immersion of three leaves during 25 hrs., in 30 min- 

 ims of a solution of one part to 875 of water, protluced the least 

 effect. The immersed leaves were then treated with carbonate of 

 ammonia, as described under nitrate of potash, and with the same 

 result. 



Potassium, Iodide of. Half-minims of a solution of one part to 

 437 of water were placed on the discs of seven leaves. In 30 m. 

 one leaf had the blade inflected ; after some hours three leaves had 

 most of their submarginal tentacles mo<lerately inflected; the re- 

 maining three being very slightly affected. Hardly any of these 

 leaves had their outer tentacles inflected. After 21 hrs. all re- 

 expanded, excepting two which still had a few submarginal ten- 

 tacles inflected. Three leaves were next immersed for 8 hrs. 40 m., 

 each in 30 minims of a solution of one part to 875 of water, and 

 were not in the least affected. I do not know what to conclude 

 from this conflicting evidence; but it is clear that the iodide of 

 potassium does not generally produce any marked effect. 



Potassium, Bromide of. Ilalf-niinims of a solution of one part 

 to 437 of water were placed on the discs of six leaves; after 22 hrs. 

 one had its blade and many tentacles inflected ; but I suspect that 

 11 



