DIGESTION 259 
seed is inoperative under these conditions. Too much 
stress must not, however, be laid upon this point, as the 
enzymes have not been prepared in any case in anything 
like a pure condition. 
Recently Vines has found that members of the ereptase 
class are very widespread in plants, occurring in almost all 
parts of them. His researches suggest that possibly the 
so-called tryptases are mixtures of peptase and ereptase. 
The action of all these proteoclastic enzymes is probably 
one of hydrolysis, though it is difficult to prove it by analysis. 
Rennet occurs in many seeds, in some cases in the germinat- 
ing, and in others in the resting, condition. It has also a 
wide distribution in the vegetative and floral parts of various 
plants. Whether it is really proteoclastic in the vegetable 
organism ig hard to say, as the details of its action are 
unknown. It is so in the animal body. 
The enzymes which decompose glucosides, as we have 
already seen, are numerous and varied in their distribution, 
occurring in various fungi and lichens as well as in the higher 
plants. Their action may be illustrated by the behaviour 
of emulsin, which exists in quantity in the seeds of the bitter 
Almond and in the vegetative parts of the Cherry-laurel 
(Prunus Laurocerasus). It splits up the glucoside amygdalin 
according to the equation 
CypHy,NO,, + 2H,0 = C,H,0 + HCN + 2(C,H,,0,) 
Amygdalin Benzoic Prussic Glucose 
aldehyde acid 
This is, as in other cases, a process of hydrolysis. Myrosin, 
another of the group, is peculiar in that it effects its character- 
istic decomposition without causing the incorporation of 
water during the process, thus: 
CigHgNK8,0,) = CsH.ONS + CyEh,0, + KHSO, 
Sulpho-cyanate Glucose ‘Potasalate 
of allyl hydrogen- 
sulphate 
Other, such as rhamnase, existing in the seeds of Rhamnus 
infectorius, erythrozym in the Madder, gaultherase in the 
17 * 
