130 Dr. A. Voelcker on the Chemical Composition of the 



he also detected a trace of organic matter, which caused the 

 watery fluid when boiling to emit an odour of boiled apples. 

 Though I have examined the water of many pitchers from four 

 different localities, and paid particular attention to the detection 

 of oxalic acid, I have failed in finding a trace of it, and I am 

 therefore inclined to believe that Dr. Turner, on account of the 

 minute quantity of solid matter which he must have got on eva- 

 poration of the water, was unable to subject the minute crystals 

 which he took for superoxalate of potash to a further examina- 

 tion, which would have shown him that the crystals were not 

 superoxalate of potash, but chloride of potassium. The propor- 

 tion of chloride of potassium which I found in the fluid is consider- 

 able ; it is deposited from the liquid after evaporation in the form 

 of minute but very regular cubes. The odour of boiled apples 

 which Dr. Turner observed I found very distinct when the water 

 was heated to the boiling-point. Besides chloride of potassium I 

 found malic and a little citric acid, in combination usually with 

 soda, lime and magnesia, and a small quantity of another orga- 

 nic matter which gave a yellow tint to the water during its eva- 

 poration. The quantity of the latter was too minute to enable 

 me to ascertain its chemical nature. 



I will now proceed to describe the experiments with the dif- 

 ferent fluids in the ascidia of Nepenthes : — 



1. Fluid from an unopened pitcher-plant grown in the Bota- 

 nical Garden, Edinburgh. 



The water which I got on the 12th of June, 1849, was per- 

 fectly colourless and clear ; it had an agreeable, not very pro- 

 nounced smell and a refreshing taste. Though its taste was not 

 sour, litmus paper showed the presence of an acid or an acid salt 

 by the red colour it assumed when dipped in the water. When 

 heated it remained clear, and only assumed a slightly yellow 

 colour when the liquid became very concentrated. The residue 

 which remained on evaporation was cream-coloured, very hygro- 

 scopic, and dissolved entirely in a small quantity of distilled 

 water. Litmus paper plunged in this solution was turned red 

 immediately ; the acid which is present in the water therefore was 

 not volatilized during the evaporation. 



The quantity of the water from one pitcher amounted to 



17*41 grains, 

 which gave on evaporation 



0-16 of dry residue, dried at 212° F. 

 100 parts of the fluid consequently contained 



0*92 per cent, of solid matter. 



2. Water from unopened pitcher-plants grown in the Botani- 

 cal Garden, Edinburgh, June 13th, 1849. 



The physical characters were the same as those of the preceding 



