4i 
Heat by Wounded Plants. 
with the experiments made on respiration, since both methods 
deal with the total reaction on masses of tissue where the 
effect cannot be localized. 
None of the other plants employed were investigated so 
thoroughly as potatoes, but enough to show that they too 
gave a distinct temperature-reaction after injury. Radishes 
were experimented with once or twice, and showed, in so far 
as the experiments could be carried, a reaction similar to that 
of potatoes. One experiment with the bell-glasses herein 
recorded (Expt. 23) remained trustworthy until after the 
maximum had been reached, but later it had to be abandoned 
as the radishes began to decay. The same trouble occurred 
with the other experiments, and for this reason radishes were 
no longer used. It was difficult at the time of year — June and 
July — when these experiments were made, to obtain carrots 
of sufficient size for use ; and they also have the disadvantage 
that the wounds when made gape open very widely after a few 
hours. Nevertheless a series was successfully finished, and 
showed very much the same results as those obtained with 
potatoes, although the temperature was lower (Expt. 15). 
This last fact may perhaps be explained by the circum- 
stance of the gaping of the wound, which thereby allowed 
more loss of heat by radiation. The maximum comes at 
a somewhat later period, and the return to normal temperature 
somewhat slower than with potatoes, but this corresponds with 
the respiration-curve previously determined 1 . In the bell- 
glasses the highest maximum yet mentioned was found, being 
I * 35 ° C. (Expt. 29), and as well the highest plus temperature 
of the normal tissue was indicated by both methods. By the 
thermo-electric method which gives the actual temperature of 
a single carrot, it was found under normal conditions to be 
o-2° C. (Expt. 16). It will be remembered that the normal 
respiration of carrots is very high, being about 15 mg. per 
hour. The swollen stem of the Kohl Rabi ( Brassica oleracea 
var. gongylodes ), and the fruit of the Cucumber, also gave 
1 Richards, Respiration of Wounded Plants, 1 . c. Expts. 14, 15, 
