~ ( 609 ) 
30°, and fore-heating times of from 1 to 24 hours, and, further 
on the consideration that we were always obliged to let an ““Antrieb” 
pass before we obtained constant values of the fermentation 
velocity. In the first place, now, we do not think the comparison of 
his experiments with ours justified: our longest fore-heating times 
lasted 20 minutes, of adaptation or growth phenomena there is 
hardly question in so short a time whereas such processes will no 
doubt occur in the long periods of RureErs’ experiments'). We even 
see in this circumstance the probable explanation of the differences in 
the course of the curves obtained by him for the relation between 
praesentation time and time of fore-heating at a temperature of 30° 
and higher. 
Moreover, even if we accepted a favourable influence, by continued 
fore-heating, as vigorous as was observed in this experiment of RUTGERS, 
that influence, during 20 minutes, i.e. our longest time of fore-heating, 
would not have been of much importance. For in the 20 minutes 
which succeed the hour of fore-heating in his experiments, the praesen- 
tation time changes only from 210" to 217", a modification falling 
within the limits of observation errors. 
Furthermore, the rising of the fermentation velocity during the 
“Antrieb’” must by no means be exclusively ascribed to the action 
of the continued fore-heating: an “Antrieb” also originates without 
heating. Hereby a number of factors will play a part: so, with 
our method of working, the glucose solution did not immediately 
penetrate into the cells. In fact, all kinds of experimental mistakes 
accumulate in this factor. 
We do not, however, intend to neglect the here meant time 
factor; it is quite certain that first the “Antrieb” must be finished 
before the temperature is able to exert its full influence. 
Let us therefore consider the significance of this factor with 
reference to the table below, which relates to special experiments 
performed for the study of that factor. 
It is clear that this table gives but a very imperfect image of the 
rate of velocity during the ‘“Antrieb”. What will be the initial 
velocity at tbe beginning of that “Antrieb”; to this we shall 
certainly get no satisfactory answer based on these experiments *). It 
1) Compare here in particular the Dissertation of Mr. Rutgers. 
2) Supposed that this “initial” velocity proved to have the value O (and to this 
our results do point), or that it was perfectly constant for all temperatures (for 
instance that of 20°C., as may be expected at another arrangement of the expe- 
riments), what, then, remains of the determination of a temperature curve for that 
initial velocity ? | 
