Green. — On Vegetable Ferments. 1 1 5 
in water, suggested that they contain a saponifying enzyme. 
Such a ferment was described by the writer in 1 890 \ as occurring 
in the seeds of Ricinus communis during the period of germina- 
tion. It can first be identified after a few days of that period 
have passed, and the endosperm is seen to be in process of ab- 
sorption. From such enlarged and swollen endosperms an 
extract should be prepared by soaking them for twenty-four 
hours either in glycerine or a solution of common salt containing 
5 per cent. NaCl, with a trace of some antiseptic such as 
KCN to prevent putrefaction. If the latter solvent be used, 
when the liquid has been strained from the pulp and filtered, it 
should be dialysed for some time to get rid of the greater part 
of the salt, as this impedes the action of the enzyme. The 
extract will then be slightly opalescent or nearly clear, and 
will contain a little proteid matter, coagulating on boiling. 
When such an extract is mixed with twice its volume of an 
emulsion of castor-oil (which should be made as thick as 
possible to approximate to the conditions obtaining in the 
cells of the seed), and the mixture is exposed to a temperature 
of 40° C. in an incubator, an acidity is soon developed in the 
liquid, which the addition of a few drops of litmus-solution at 
once makes evident. If the operation be carried out in a 
dialyser, the liquid outside the membrane does not share the 
acidity, showing that the latter condition is due to something 
that cannot diffuse out of the dialyser. This body can be 
extracted from the contents of the latter by shaking them up 
with -2 per cent. NaHO, and filtering. If the resulting 
alkalinity be neutralised with a mineral acid, a quantity of 
fatty acid soon rises as a scum to the surface. 
If the digestion be allowed to go on in the dialyser for some 
days, glycerine can be detected in the dialysate. 
If the extract be boiled before mixing with the emulsion no 
such decomposition takes place. The transformation is there- 
fore shown to be due to the action of an enzyme, capable of 
splitting up oil into fatty acid and glycerine. 
1 Green, On the germination of the Castor-oil plant, Proc. Roy. Soc., vol. 
XLVIII, 1890, p. 370. 
