430 



Miss J. White. The Ferments and [Mar. 3, 



seeds thus treated were afterwards tested for their germinative capacity and 

 their enzyme reactions, the former of which was found to be entirely lost in 

 each kind of seed used, while the latter was still evident, though in certain 

 cases it was markedly diminished. 



The highest temperature at which the slightest possible traces of enzyme 

 reactions remained visible was 130° C, when faint signs of saccharification 

 of starch were produced by the diastase extracted from resting grains of 

 barley subjected to this temperature. Throughout this series of experiments 

 only fresh seeds were employed, whose germinating capacity before exposure 

 to the high temperatures was approximately 100 per cent. 



After the grains had been heated above 120° C. the nature of the 

 precipitates was apparently changed. While the bulk of the precipitate was 

 seemingly as copious or even more so than before the heating of the seeds, 

 it was much more soluble in water than that obtained from the same material 

 unheated, and the filtrate was thinner and less glutinous than before. This 

 was especially pronounced in the rye, for the filtering process in this case 

 lasted about two hours, while the same process with the fresh seeds which had 

 not been exposed to high temperatures occupied as many days. 



The tables appended below show the results of these experiments in detail, 

 i.e. the effects produced in the seeds on exposure to abnormally high 

 temperatures ; the effects of extremely low temperatures on the seeds will be 

 dealt with later. 



The methods of precipitating both the diastase and the proteolytic 

 enzymes were the same as those employed in the preceding section of the 

 paper. 



Briefly summarising the results set down in the tables, it is found that the 

 most resistant of all the ferments to extremes of heat is the diastase of 

 barley, which is not absolutely destroyed till the grains have been heated to 

 131° C. for an hour. The least resistant of the enzymes is apparently the 

 fibrin-digesting enzyme, for it is destroyed entirely at 124° C. in every kind 

 of seed tried. This result may, however, possibly be connected with the fact 

 that the quantity of this ferment present even in the fresh grains is 

 extremely small. 



Whether the slight variation in the resistant power of the diastatic and 

 proteolytic enzymes of different grains to dry heat indicates the existence of 

 specific varieties of the different enzymes must remain for the present an 

 open question, but in any case the most exact experiments merely indicate 

 that the ferments in question are no longer capable of extraction and do not 

 say whether they have been actually destroyed or merely coagulated and 

 rendered insoluble. The coagulation temperature in the different seeds might 



