t 1 4 Vines. — The Proteases of Plants (IV). 
in different stages of germination, contained an ereptase, inasmuch as the 
material actively digested Witte-peptone as shown by the tryptophane- 
reaction ; but ‘ at no time could any evidence of the presence of an enzyme 
capable of attacking the proteids of the seed be obtained.’ ‘ The enzyme 
acts on the proto-proteose, the hetero -proteose, and the deutero-proteoses, 
separated from Witte-peptone ; it is quite inactive on phaseolin of the 
bean, excelsin of the Brazil nut, edestin of the hempseed and boiled fibrin.’ 
The author concludes as follows : — ‘ There can be no doubt but that 
the large proteid store in bean-seeds is utilized in germination, and in all 
probability this utilization is preceded by cleavage to the amido-acids, 
hexon bases, & c. What effects this cleavage, and what part, if any, the 
ereptase plays, are unsolved problems.’ It should be noted that the times 
of digestion mentioned in the various experiments were 41, 19, and 18 
hours. 
Dean’s second paper gives an account of more minute investigations 
into the chemistry of the seeds of Phaseolus vulgaris , with results that 
confirm the main conclusions of the first paper. He says : ‘ The results of 
this study have shown that, as was to be expected, the proteids of the seed 
undergo proteolysis during germination as a preliminary 'to the transportation 
of the nitrogen and its utilization in the formation of new organs. There 
are three ways in which this process might be carried out : by the action of 
a tryptic enzyme ; by the combined action of the protoplasm and of an 
enzyme which is, by itself, incapable of carrying out the whole process ; or 
by the action of the protoplasm alone. The results of a study of the 
proteolytic enzymes of the resting and germinating bean show that there 
is no enzyme present which is able to digest the proteids of the seed. 
There is present, however, an enzyme of the ereptase group which is 
capable of digesting the proteoses resulting from the partial hydrolysis of 
the seed proteids. It may be, therefore, that the protoplasm of the cells 
starts the process of proteid decomposition, and carries it to some stage at 
which the ereptase takes up the work and completes the process.’ 
Experiments with Seeds. 
I turn now to my own observations. Until recently, I had not specially 
investigated seeds, having only made a few incidental experiments in 
connexion with the determination of the general occurrence of ereptase in 
plant-tissues. The first experiments, described in my paper on ‘Trypto- 
phane ’ ( 4 ), were made with Malt and with Vicia Faba , and showed that 
extract of Malt readily undergoes autolysis, whereas, in the case of Vicia , 
no autolysis could be detected in 20 hours, though Witte-peptone was more 
or less peptolyzed in 24 hours. I took occasion to point out at the time that 
‘ the whole subject requires systematic reinvestigation ; ’ and the experi- 
ments described in this paper are a first attempt to satisfy that requirement. 
