550 Richards . — The Respiration of 
also discovered that, in a diminished quantity of oxygen, plants 
require a period of accommodation to the new conditions, during 
which time the respiration rises perceptibly. All of these 
results show, in common with what has been described here, 
that, under conditions which are unnatural, plants strive to rid 
themselves of, or surmount, the irritating influences of this 
unnatural state by a temporary increase of their vital energy. 
In considering respiration as a measure of such increased 
activity, it must be remembered that in all these cases, and in 
the case of the work herein described, the methods necessarily 
employed show only the total effect of the injury upon the 
plants concerned. That is to say, it is impossible to locate 
the active region, to say whether it really is the whole potato, 
for instance, or only the part near the wound, which is affected, 
and which therefore respires more rapidly. In considering 
other effects of injury, Hauptfleisch 1 has shown that the 
movement of the protoplasmic contents of the cells is greatly 
increased in the neighbourhood of a wound, and that the 
activity so produced is transmitted to other cells after the 
lapse of a certain time. That this stimulation is carried to 
all the cells of the entire plant would hardly be supposed, 
nor does it seem to be the case from what Hauptfleisch 
records. In some comparatively delicate water-plants, as 
Elodea and V allisneria , it was indeed seen to be propagated 
for a considerable distance ; but in examples of hardier tissues, 
such as those of Zea Mais or Triticum , it seems to be much 
more restricted. In the experiments recorded here, indica- 
tions of a more or less restricted zone of activity are suggested 
by the ever-increasing rate of respiration which followed 
successively severer injuries. That there may be a connexion 
between the phenomena which Hauptfleisch describes as 
f secondary streaming ’ and the increased rate of respira- 
tion after injury is not at all improbable, in that they are 
all but part and parcel of the general stimulation of the 
normal functions of the plant. 
1 Pring’s Jahrb., Bd. xxiv, p. 19 1 et seq., 1892. 
