Some Problems of Reproduction.—II

ABSTRACT

Recent researches on the utilisation of reserves in plants had shown that in every case examined a ferment or enzyme was present which, under suitable circumstances, could effect in vitro the same process, usually of hydrolysis, which the living organism performs. Thus, if the green cell, under the influence of light, accumulates starch as a reserve during the day, and this starch is removed as a soluble sugar during the night, a diastatic ferment can be isolated from these green cells, and will operate the same conversion. So, too, from germinating seeds we can extract a peptonising ferment which, like trypsin, will hydrolise proteids into peptones and beyond, yielding leucin, tyrosiu, and other amides, such as asparagin. From this consideration on the one hand, and from the observations of Krukenberg, Le Dantec, Miss Greenwood, and A. Dixon and myself on the digestive processes and ferments of Protista of animal habit, it appeared probable that in cases where a cell utilises the reserves stored up in its own interior, enzymes would also prove to be present.