Fluid in the Ascidia c/' Nepenthes. 199 



and boiling was filtered hot, and alcohol and ammonia added to 

 the clear liquid. The addition of alcohol produced a voluminous 

 white precipitate, a reaction which indicates the presence of malic 

 acid. The quantity of this precipitate was much larger than that 

 of the lime precipitate which citric acid gave. The formation of 

 a precipitate, upon addition of alcohol to the liquid from which 

 the first had been separated by filtration, is chai'acteristic of the 

 presence of malic acid, for no other lime-salts were present ; for 

 instance, no sulphate of lime was present which could have pro- 

 duced a precipitate. But I thought it nevertheless necessary 

 to examine the precipitate caused by the addition of alcohol 

 further. When burnt it turned black, gave off pungent vapours, 

 and was converted into carbonate of lime. The solution of chlo- 

 ride of calcium and ammonia used for the experiment remained 

 clear after the addition of alcohol ; the acid liquid likewise re- 

 mained clear when alcohol was added ; both put together imme- 

 diately produced a white voluminous precipitate. 



Basic acetate of lead, as already mentioned, throws down from 

 the solution a white precipitate. I could not observe that this pre- 

 cipitate melted below the boiling-point of water, as pure malate of 

 lead does, but it must be remembered that this reaction is di- 

 stinctly marked only when the malate of lead is pure ; admixtures 

 of other salts of lead prevent it altogether ; and as I have shown 

 the presence of citric acid and another organic substance which 

 is thrown down by basic acetate of lead, there can be no doubt 

 that this was the reason why the precipitate did not dissolve in 

 boiling water. 



Though I have not been able to obtain a sufficient quantity of 

 the acids oi Nepenthes for an elementary analysis, I think the above 

 reactions prove the presence of malic and citric acid. Oxalic acid, 

 which is readily detected, as the weakest solution of an oxalate is 

 thrown down by lime-water, I failed to discover; on the contrary, I 

 have shown that the water contained lime, which excludes the co- 

 existence of oxalic acid in a clear liquid. I have found that the 

 smallest quantity of oxalic acid immediately caused the water of 

 Nepenthes to become turbid. 



The second half of the residue left on evaporation of the mixed 

 fluids I exposed to a red heat in a platinum capsule. It turned 

 black, gave off pungent fumes, and left a white salt after all the 

 charcoal was burnt off. 



On analysis this residue was found to consist of 



Chloride of potassium 76-31 



Carbonate of soda 16'44 



Lime 3-94 



Magnesia 3*94 



100-63 



