. The presence of
acidity is essential for the hydrolysis to take place, the most suitable
strength being one-tenth normal, and the degree of hydrolysis is
proportional to the quantity of ferment present. Sulphuric, phosphoric,
acetic or butyric acids, or sodium bisulphate, may be used without much
influence on the result. Butyric acid is stated to be the best, but in
practice is too expensive, and acetic acid is usually adopted. The
emulsified mixture should be allowed to stand for twenty-four hours, and
the temperature should not exceed 40 deg. C.; at 50 deg. C. the action is
weakened, and at 100 deg. C. ceases altogether.

Several investigators have since examined the hydrolysing power of
various other seeds, notably Braun and Behrendt (_Berichte_, 1903, 36,
1142-1145, 1900-1901, and 3003-3005), who, in addition to confirming
Connstein, Hoyer and Wartenburg's work with castor seeds, have made
similar experiments with jequirity seeds (_Abrus peccatorius_)
containing the enzyme abrin, emulsin from crushed almonds, the leaves of
_Arctostaphylos Uva Ursi_, containing the glucoside arbutin, myrosin
from black mustard-seed, gold lac (_Cheirantus cheiri_) and crotin from
croton seeds. Jequirity seeds were found to have a stronger decomposing
action on lanoline and carnauba wax than the castor seed, but only
caused decomposition of castor oil after the initial acidity was first
neutralised with alkali. Neither emulsin, arbutin nor crotin have any
marked hydrolytic action on castor oil, but myrosin is about half as
active as castor seeds, except in the presence of potassium myronate,
when no decomposition occurs.

S. Fokin (_J. russ. phys. chem. Ges._, 35, 831-835, and _Chem. Rev.
Fett. u. Harz. Ind._, 1904, 30 _et seq._) has examined the hydrolytic
action of a large number of Russian seeds, belonging to some thirty
different families, but although more than half of these brought about
the hydrolysis of over 10 per cent. of fat, he considers that in only
two cases, _viz._, the seeds of _Chelidonium majus_ and _Linaria
vulgaris_, is the action due to enzymes, these being the only two seeds
for which the yield of fatty acids is proportional to the amount of seed
employed, while in many instances hydrolysis was not produced when the
seeds were old. The seeds of _Chelidonium majus_ were found to have as
great, and possibly greater, enzymic activity than castor seeds, but
those of _Linaria_ are much weaker, twenty to thirty parts