22 
QITINOLOGY OF THE EAST INDIAN PLANTATIONS. 
solution. It seems . . . that the coloured rays of light which are the most active, in a chemical point of 
view, are those which least favour the decomposition of carbonic acid.” 
Since writing the above, I have met with a paper by M. Boussingault* which seems strongly to confirm 
the views I have expressed. He shows that a plant is exposed during the whole course of its existence to 
two opposing forces in connection with the general and the chlorophyllian respiration, the one tending to 
add and the other to abstract the material ; and that according to the relation between these two forces, 
governed, as they are, by the intensity of light and of temperature, a plant will emit either oxygen or 
carbonic acid in variable proportions. In a feebly illuminated locality a plant remains in some sort 
stationary during whole months; and in absolute darkness, the eliminatory force being the only one in 
existence, the plant can only live upon its own resources, emit carbonic acid by combustion of these, and 
finally perish without increase of weight. 
[Further, and which is more expressly to my purpose, M. Boussingault says that “ at certain epochs, in 
certain organs, the plant becomes, like an animal, an apparatus of combustion, — it burns carbon and 
hydrogen, it produces heat,” and “ a plant grown in darkness really behaves like ( se comporte comme ) an 
animal during the whole duration of its existence.” An animal of the most simple organization not only 
produces heat through respiration, and emits carbonic acid, but a certain portion of the albumen which it 
contains is modified by the respiratory combustion into a crystalline, nitrogenized compound (urea). In the 
respiratory combustion of a plant growing in darkness, a like modification of the albumen could scarcely be 
as palpable, from the want of excretory organs; but we find in the juice filling the cells a crystalline 
immediate principle (asparagine) , which, like the other, is an amide , becoming as easily transformed into 
aspartate of ammonia, as the former into carbonate of ammonia. 
Thus the asparagus plants,! whilst flourishing in the light of the sun, produce no asparagine, but this 
is formed as a result of the general respiration when the light is excluded. It is easy to see how strongly 
these experiments confirm the results of the exclusion of light in the process of mossing adopted by Mr. 
MTvor. It is remarkable that green light is nearly the same in its effect as darkness, so that the shade of 
trees producing this coloured light is unfavourable to the development of vegetation. On the other hand, 
the products of the etiolated vegetation must be better adapted to sustain the life of those insects which 
always attack, in preference, plants of enfeebled organization. 
The Woody Fibre of the Bark. 
In order to complete my review of the question whereabouts in the bark the alkaloids are situated, and 
to put the reader in some measure in possession of the views of others on the subject, I will subjoin! a trans- 
lation of a paper on this special subject by Dr. Fluckiger, of Berne, presenting, as I think, the most recent, 
as well as the most correct views of the subject. It will be seen that the opinions of this talented observer 
are fully in accordance with those which I have expressed ; and, as it seems to me, that he has, by well- 
devised experiments, shown that the views of Schacht and Wigand are not capable of being sustained. 
I here present to the reader the results of some experiments of my own, tending to show more fully, 
and in different barks, the actual contents in alkaloid of the liber and of the cellular envelope. 
Experiments. 
The following experiments were instituted with a view of further comparison of the contents of the 
liber and of the cellular envelope. The plan adopted was the same that I have previously described. A 
* “ De la vegetation dans l’obscurite” (Ann. de Chimie et de Physique, Fev. 1868). 
f And others capable of producing asparagine ; the same holds good as to solanine from the potato. 
I In the Appendix. 
