Vines.— The Proteolytic Enzyme of Nepenthes. 579 
My observations lead me to results differing widely from 
those of von Gorup-Besanez. I find, in the first place, that 
the digested liquid always gives a precipitate with nitric acid, 
giving a clear yellow liquid on warming which again becomes 
turbid on cooling, as also a precipitate with potassium 
ferrocyanide and acetic acid*: the biuret-reaction is well 
marked. On neutralization, there is a precipitate, dense 
when the digestion has been of short duration (two hours), 
which consists presumably of parapeptone. After filtration 
from this precipitate, the neutral liquid gives only a slight 
turbidity on the addition of nitric acid, though it contains 
much proteid : hence the substance precipitated by nitric 
add is probably some parapeptone not precipitated on 
neutralization. 
On concentrating the neutral liquid on the water-bath 
to one-third or one-fourth of its bulk, and then filtering 
into alcohol, a considerable precipitate is formed. The 
alcohol having been removed by filtration, the precipitate 
on the filter mostly dissolves in a small quantity of distilled 
water, the solution giving the following reactions : (1) no 
precipitate with nitric acid, but a strong xanthoproteic 
reaction ; (2) a precipitate with potassium ferrocyanide and 
acetic acid ; (3) a striking biuret-reaction ; (4) a dense 
precipitate on saturation with ammonium sulphate, the filtrate 
from which gives no proteid reactions. From this I conclude 
that the main product of digestion is a proteid of the nature 
of an albumose, allied, by its not being precipitated with 
nitric acid, to the body known as deutero-albumose. I failed 
to detect the presence of a true peptone, that is, of a proteid 
which is not precipitated on saturation with ammonium 
sulphate. 
I have tested the dialysing properties of the proteid pre- 
cipitated by alcohol, and find that after twenty-four hours 
the water outside the dialyser gives a slight xanthoproteic 
reaction, but no biuret, though the liquid in the dialyser 
gives both reactions very strongly ; whence I conclude that 
there is no readily dialysable proteid present. 
