52 
oak and sycamore, the young shoots of which are so often 
tinged of a lively red, do not turn red in fading, hut yellow, 
from which it may he inferred that the process of decay in 
leaves does not lead hack to the same stage at which that 
of development commenced. 
The autumnal purple coloration of leaves is met with in a 
few native plants, notably the bryony, the privet, and the 
dogwood. It imparts a dingy hue to the leaves, and is there- 
fore not much noticed. I observed a case of its occurrence 
last summer, which I had not previously seen mentioned. 
Passing through a field of corn, which was then nearly ripe, 
I saw a number of plants by the sides of the path with 
blades distinctly purple. On closer observation it was 
evident that in all cases where this coloration occurred the 
ears of corn had been cut off before ripening, the act pro- 
bably of idle passers-by, those plants which remained unin- 
jured having become yellow as usual. I inferred that it 
was the injury sustained by the plant, and the arrest of its 
main function, that of the development of seed, that had led 
to the formation of some purple substance, not seen during 
the process of natural decay. I made some experiments on 
this purple colouring matter, but all I can say about it is, 
that it belongs to the same class as the red and yellow 
colouring matters of faded leaves. I anticipated the possi- 
bility of its being identical with a product of the decomposi- 
tion of chlorophyll, crystallising in purple needles, which I 
had discovered in the course of my investigation, but I was 
disappointed in my expectation. 
As regards the nature of the colouring matters to which 
the various colours of faded leaves are due, opinions vary. 
It is generally supposed that they are formed from chloro- 
phyll by some process of decomposition, probably of oxi- 
dation, and nothing can be more natural than this supposi- 
tion. On exposure of the leaf to light and air, after its vital 
functions have ceased, the green colour due to chlorophyll 
