onwards, and this must be attributable to some harmful influence. 
I supposed that this influence was already observable at 30° and 
therefore tried to show it in another way. I made a series of 
experiments in which I first observed the peas at 20°, then warmed 
them to a higher temperature and again observed them at 20°. The 
observation times were of course chosen in such a way that the 
peas could properly regain the temperature; first of all it was 
ascertained whether a change of temperature as such had any in¬ 
fluence, by making experiments at 5°—-25°—5°. No such influence 
was found; my results agree completely with those of Ziegenbkin 1 ) 
in contradistinction to those of Zalenski*) and Palladin *), who 
ascribe a powerful influence to changes of temperature. 
Now in these experiments I found a falling-off, in consequence of 
the harmful effect of heating to 40° and higher; this falling-off was 
very small after warming to 35°. so small that the effect was doubtful; 
an exposure to 30° did not produce any decline at all. In this way 
also therefore no conclusion could be reached. It was indeed found 
by warming for various periods to 43°, that the decline for 15 min., 
V, hour, 1 hour and l 1 /, hours, when plotted, gave a logarithmic 
curve. The slowing of the respiration by warming to 40° was found 
to have disappeared completely after 8 hours. 
After this I extended the experiments to Triticum vulgare and to 
Lupinus luteus. 1 only investigated the respiration in successive periods 
at temperatures of 0°—50°. The seedlings were treated as in the case 
of Pisum; they were, however*, left one day longer on saw dust. 
For Lupinus luteus I obtained the following results for 100 seedlings. 
(See following table p. 225). 
It results from these figures: o • 9 6 on 
That, the coefficient for a temperature interval of 10 is 
determining the ratio by taking for A it the respiration 
first hour, we find 2.4; by taking the mean of my other date thl * 
even becomes 2.5. The rule of van *t Hoff-Arrhenius seem 
apply here up to 25°. At 25° a certain decline is already noti 
and at 40° this shows a logarithmic curve. t j ian 
In general Lupinus is less resistant to a high tempera . 
Pisum; after 6 hours at 45° the turgescence of the roots had P ^ 
disappeared. As regards Blackman’s theory, Lupinus g nes 
general result as Pisum. ^ lg93 
1) E. Ziegenbein, Jahrbiicher fur wissensch- Botanik, Bd. p ‘ 
>) W. Zalenski, Abstract in Bot. Centralblatt, Bd 95, P- »•^ ' 
*) w. Palladin, Revue g6nerale de Botamque, t. Xt, p. 2 , 
