358 
POPULAR SCIENCE REVIEW. 
pendently of Mr. Darwin, the separation of a substance closely 
resembling pepsin from the viscid secretion of Drosera 
dichotoma. He placed side by side plants of the common 
Drosera rotundifolia , some in the normal state, others with the 
roots pinched off close to the rosette, and with the leaves all 
buried, only the budding flower-stalk appearing above the sand ; 
others with the roots and flower-stalk left on, but all the leaves 
pinched of, the roots being buried in the sand; and others 
again with the roots left on but appearing above the sand, some of 
the leaves buried and others exposed. These plants were all care- 
fully washed with distilled water, before being planted in silver 
sand which had deen deprived of all organic matter, carefully 
watched to prevent flies being caught ; and were then fed, some 
with pure distilled water, others with a strong decoction of 
beef, and others with a very dilute solution of phosphate of 
ammonia. The conclusions arrived at from the series of experi- 
ments were that the plant can not only absorb nutriment by its 
leaves, but that it can actually live by their aid alone, and that 
it thrives better when supplied with nitrogenous material in 
small quantity. The nitrogenous matter is more readily 
absorbed by the leaves than by the roots, over-feeding killing 
the plant sooner through the leaves than through the roots 
alone ; although the roots also certainly absorb nitrogenous 
matter. This absorption of nutrient material through the 
leaves is in harmony with the fact already mentioned, of the 
vitality of the leaves long after separation from the plant. 
We are not acquainted with any special organ by which the 
processes of absorption and digestion are effected ; indeed, almost 
everything connected with their modus operandi remains for 
the present in obscurity. It seems likely that the papillae 
which abound on the upper surface of the leaf and on the 
pedicels of the tentacles have some share in them; and possibly 
also certain other bodies which are not described by Mr. 
Darwin, nor by any other observer as far as I am aware. 
These bodies, which I propose provisionally to call “ ganglia,” 
are represented in fig. 7, and are found, on making a careful 
dissection of the leaf, immediately beneath the epidermis of 
the upper surface, and on the pedicels of the tentacles. They 
consist of from two to four cells, much smaller than the ordi- 
nary cells of the mesophyll of the leaf, and have the appearance 
of centres from which the cell-walls radiate. They are filled 
with a brownish-green granular, presumably protoplasmic sub- 
stance. I have not observed bodies of a similar character except 
in plants* whose foliar organs possess the power of digestion. 
* With the exception of Callitriche, in which bodies of a similar character 
produce the so-called u rosulate ” appearance of the leaves, and were long 
ago described as glands by the late Dr. E. Lankester. 
