580 Vines, — The Proteolytic Enzyme of Nepenthes. 
In most cases the investigation of the products of digestion 
was proceeded with immediately after digestion : but in one 
case I kept the proteids precipitated by alcohol, in alcohol, 
for nearly a year, without finding their solubility in water 
or their reactions in any way altered. The duration of the 
digestion was varied in different cases, from as short a time as 
two hours, to as long a time as six days ; the only perceptible 
difference in the nature of the products being that in the case 
of the brief digestions a much larger quantity of parapeptone 
was present. In some of the digestions I have used as much 
as ten grammes of fibrin ; more often five or six grammes : 
the digestive liquid usually contained about o-3 °/ 0 HC 1 , and 
the amount of liquid was about 20 c.cm. to each gramme of 
fibrin, of which nearly half consisted of pitcher-liquid. 
I have endeavoured to determine the nature of the ultimate 
products of digestion, but without complete success. I find 
that if the digested liquid be neutralized and be allowed 
to stand for some hours, a deposit gradually collects on the 
walls of the beaker. Under the microscope this substance is 
seen to consist of minute round granules, cohering in rows 
and in clumps, or of vacuolated oily drops. On carefully 
evaporating some of this with nitric acid, and then adding 
a drop of caustic soda, a deep brown colour is produced 
(Scherer’s test for leucin). I have obtained apparently 
the same substance from the precipitate formed when 
the digested liquid is dropped into alcohol. The dense 
precipitate is not wholly soluble in cold distilled water ; and 
when hot water is poured over the insoluble residue on the 
filter a turbid liquid passes through. This liquid becomes 
clear on heating, but reprecipitates on cooling ; it also be- 
comes clear on the addition of acids and alkalies, and gives 
the foregoing colour-reaction on treatment with nitric acid 
and caustic soda. It gives a faint yellow colour on the 
addition of ammonia, after boiling with nitric acid ; and 
a precipitate with Millon’s reagent, which turns partly red 
and partly yellow on heating : on adding caustic soda in 
excess and a small quantity of solution of copper sulphate 
