52 Laidlaw and Knight —A Description of a Recording 
hoped to publish shortly, that the stomata upon different parts of a leaf may 
be considered to behave similarly under similar conditions of illumination, 
&c.j so that the curves in Fig. 2 are an indication of the relative accuracy 
of the recording apparatus and the ordinary porometer. The maxima in 
the curve of the latter are repeated in both recorder curves, and altogether 
here is a striking parallelism. 
Stomatal Behaviour during Wilting. 
It has been stated by Darwin (4, 5) and Darwin and Pertz (6) that, in 
the case of plants investigated by them, on severing a leaf from the stem 
and allowing it to wilt, there occurs a temporary opening of the stomata 
prior to the closure following upon wilting. This preliminary opening has 
been demonstrated by the above authors by three different methods at 
different times — by the horn hygroscope, by temperature methods (in 
which, however, the assumption is made that the amount of transpiration 
from a leaf is an indication of the condition of its stomata), and also by the 
porometer method. Lloyd (7), using his alcohol method of stomatal 
