574 Vines . — The Proteolytic Enzyme of Nepenthes. 
of chloroform-vapour, I obtained complete solution of 0-05 grm. of 
fibrin in three hours. 
Chemistry of the Pitcher-liquid. 
Our knowledge on this point is very incomplete. So far 
as I am aware, the only chemical examinations of it which 
have been made are, first, that recorded in the Botanical 
Magazine for 1828, and, secondly, the analysis made by 
Voelcker in 1849. The former account states that the liquid 
in the unopened pitcher of Nepenthes distillatoria ‘ had a sub- 
acid taste, which increased after the rising of the lid, when 
the fluid slowly evaporated. My friend Dr. Turner perceived 
it to emit, while boiling, an odour like baked apples, from 
containing a trace of vegetable matter, and he found it to 
yield minute crystals of superoxalate of potash on being 
evaporated to dryness.’ Voelcker 1 found that the liquid from 
unopened pitchers of species of Nepenthes (names omitted) 
gave a dry residue which varied from 0-27 to 0*92 °/ 0 , of 
which about two-thirds consisted of incombustible ash ; he 
estimates its percentage composition as follows : — 
Malic and citric acids . . . 38-61 
Potassium chloride .... 50-42 
Soda ...... 6-36 
Lime ...... 2-59 
Magnesia ..... . 2-59 
The liquid obtained from the pitchers may be generally 
described as slightly opalescent, colourless, and somewhat 
viscid, especially when drawn from unopened pitchers. Its 
reaction varies from neutral to acid, but the conditions of 
this variation are undetermined. Hooker states that the 
liquid is always acid, whilst von Gorup-Besanez describes 
the liquid from ‘ unstimulated ’ glands as neutral or very 
slightly acid, whilst that from ‘ stimulated ’ glands (N. Phyl- 
lamphora and N . gracilis) was distinctly acid. Again, Goebel 
found the liquid in unopened pitchers of N. paradisaica to 
1 Voelcker, Ann. and Mag. of Nat. Hist., IV, 1849, p. 128. 
