352 
POPULAR SCIENCE REVIEW. 
property of living protoplasm, whether animal or vegetable. 
We were taught in our childhood that while animals inhale 
oxygen and exhale carbonic acid, the respiration of plants is of 
an exactly opposite character ; vegetable physiologists now tell 
us that the true process of respiration which all plants perform 
consists, like that of animals, in an exhalation of carbonic acid 
gas. It was formerly believed that starch was never produced 
by animals, while it is always formed by plants at some period 
of their existence; we now know that fungi never produce 
starch, while on the other hand it has been found in the tunics 
of the Salpge. Even the last refuge of those who still main- 
tained the essential distinction of the two kingdoms — that the 
food of animals is organic while that of plants is inorganic — 
must now be abandoned. 
This is, however, no recent discovery in particular cases. The 
plants known as parasites, whether phanerogamic or fungi, the 
mistletoe and dodder, or the potato-blight and mildew, live 
entirely on the already assimilated food-materials found in the 
tissues of the “ hosts ” on which they are parasitic. But in all 
these instances the nutritive material is absorbed by the plant 
in a manner similar to that in which the majority of vegetables 
derive their nourishment from the soil ; in the case of flowering 
plants through root-like organs or “ haustoria,” and in the case 
of fungi through a mycelium, which penetrates deeply into the 
tissue of the host. The point of greatest interest to physiologists 
in the facts brought out in Dr. Hooker’s inaugural address to 
Section D, at the meeting of the British Association at Belfast, 
in 1874, and more recently in Mr. Darwin’s latest publication,* 
is that certain plants have the power of absorbing the material 
required for their food — not only through the root, but also 
through the tissue of the leaf by means of certain special organs, 
aided by most elaborate and beautiful mechanical contrivances. 
The first announcement of this fact was the more startling, in- 
asmuch as the most recent experiments appear to have demon- 
strated that leaves are quite incapable, except under the most 
exceptional circumstances, of absorbing pure water, either in the 
liquid or gaseous condition. 
The number of genera in which this power has been demon- 
strated with more or less certainty is about thirteen, ten of 
which are described more or less minutely in Mr. Darwin’s 
work. Of these genera three only are British ; two of these 
have species which are common and readily accessible, and to 
them we propose mainly to direct attention in the present 
paper. 
Few lovers of plants have not gathered and admired the 
* “ Insectivorous Plants.” By Charles Darwin, M.A., F.R.S., &c. 
London: J. Murray, 1875. 
