Notes on Recent Literature. 
case of leaves with a waxy covering he compared the normal leaf 
with one stripped of its waxy covering, but in the case of a glossy 
leaf he could not compare with one stripped of its upper epidermis 
and therefore used as control the dull under surface of a leaf of 
the same species. This introduced an error which somewhat 
vitiated his work, in that he did not seem to realise that the under 
surface was usually stomatal, the upper non-stomatal, and thus the 
difference obtained was probably not solely to be traced to the 
different power of reflection of the two surfaces, but partly to the 
greater transpiration from the under surface having a cooling effect. 
Since, however, the temperature was higher when the undersurface 
was exposed, the result obtained is probably genuine. He made 
attempts to avoid the error due to difference of evaporation by 
shortening the time of exposure, so that the temperature of the leaf 
should not much exceed that of the air around, but the error still 
probably remained considerable. 
The comparison given by him of wetted and dry leaves is 
almost valueless, if the difference is attributed to the different 
reflecting powers of the two surfaces, since it is probably almost all 
due to the cooling of the wet leaf by evaporation of the water. 
The results show that in each case the covering investigated, 
hairs, wax, &c., &c., acts as a protection from too great heating by 
the radiation received. The temperature was always lower when 
such a covering was present, the difference produced by a thick 
covering of hairs amounting to as much as 37'5° C. 
He made no experiments on the effect of different colouration 
of leaves, e.g., leaves containing anthocyan. 
A contribution from a different point of view was recently made 
by Moler, who quoted Tischler’s view that red colour was an 
adaptation for a severer climate in that leaves better provided with 
reserve material were able to withstand frost better. He thought 
that the red forms were better adapted for assimilation and stored 
up more reserve. Moler found in opposition to this that the red 
forms are more sparsely provided with chlorophyll. By means of a 
special spectroscope he could obtain side by side the spectra of two 
solutions lighted by two equal lamps. On thus comparing the 
chlorophyll solution from a normal green leaf and from a leaf of the 
same species containing anthocyan under equal conditions, he 
invariably found the chlorophyll weaker in the red leaf. The 
apparatus is not fully described in this preliminary note, but he does 
not state whether he first of all got rid of the anthocyan or whether 
it remained to disturb the effect of the chlorophyll solution obtained 
from the red leaf. 
The results when fully obtained will be valuable not for the 
light they throw on Tischler’s unimportant theory, but because we 
shall have some quantitative idea of the total amount of absorbing 
pigment, whether red or green, in a leaf containing anthocyan, 
compared with that in a green leaf of the same species. 
Wiesner has described experiments carried out to establish the 
protective effect of division into small parts, or of a form, such as 
that of a linear leaf, where the surface is very great relative to the 
volume, upon the internal temperature of such finely divided or 
linear leaves or plant parts. He placed at the focus of a powerful 
convex lens exposed to clear sunlight a number of experimental 
