Volume 1

The Riverside natural history / edited by John Sterling Kingsley ; articles by C.C. Abbott [and others].

Date:
[1888], ©1888
Catalogue details

Licence: Public Domain Mark

Credit: The Riverside natural history / edited by John Sterling Kingsley ; articles by C.C. Abbott [and others]. Source: Wellcome Collection.

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    an elm-tree, a lily, or a fern, in having organs of sight, of hearing, of smell, of locomo- tion, and special organs of digestion, circulation, and res])iration, but these plants also take in and absorb food, have a circulation of sap, respire through their leaves, and some jilants are mechanically sensitive, while others are endowed with motion — certain low plants, such as diatoms, etc., having this power. In plants the assimilation of food goes on all over the organism, the transfer of the sap is not confined to any one portion or set of organs as such. It is always easy to distinguish one of the higher plants from one of the higher animals. But when we descend to animals like the sea-anemones and coral-polyi^s, which were called zoojjhytes from their general resemblance to flowers, so striking is the external similarity between the two kinds of organisms, that the early observers regarded them as ‘ animal flowersand in consequence of the confused notions originally held in regard to them, the term zoophytes has been perpetuated in works on systematic zoology. Even at the present day the compound hydroids, such as the Sertularia, are gathered and pressed as sea-mosses by many persons who are unobservant of their jieculiarities, and unaware of the complicated anatomy of the little animals filling the different leaf-like cells. Sponges, until a late day, were re- garded by our leading zoologists as plants. The most accomplished naturalists, however, find it impossible to separate by any definite lines the lowest animals and plants. So-called plants, as Bacterium., and so-called animals, as Brotamoeba, or certain monads, which are- simple sj)ecks of protoplasm, without genuine organs, may be referred to either kingdom; and indeed, a number of naturalists — notably Haeckel — relegate to a neutral kingdom (the Protista) certain lowest plants and animals. Even the germs (zoospores) of monads and those of other flagellate infusoria, may be mistaken for the spores of plants; indeed the active flagellated spores of plants Avere described as Infusoria by Ehrenberg ; and there are certain so-called flag- ellate Infusoria so much like low plants (such as the red snow or Brotococc^is), in form, deportment, mode of reproduction, and appearance of the spores, that even now it is possible that certain organisms placed among them are plants. It is only by a study of the connecting links between these lowest organisms, leading up to what are undoubted animals or jjlants, that we are enabled^to I’efer these beings to their proper kingdom. “ As a rule, plants have no special organs of digestion or circulation, and nothing approaching to a nervous system. Most plants absorb inorganic food, such as car- bonic acid gas, water, nitrate of ammonia, and some phosphates, silica, etc., all of these substances being taken up in minute quantities. Low fungi live on dead animal matter, and promote the process of putrefaction and decay, but the food of these organisms is inorganic particles. The slime-moulds called Myxomycetes, however, envelop the plant or low animals, much as an Amoeba throws itself around some living plant and absorbs its protoplasm ; but the Myxomycetes, in their manner of taking food, are an exception to other moulds. The lowest animals swallow other living animals whole or in pieces ; certain forms near Amoeba bore into minute algae and absorb their protoplasm; others engulf silicious-shelled plants (diatoms and desmids) and absorb the proto2)lasm filling them. No animal swallows silica, lime, ammonia, or 2>hos- phates as food. On the other hand, plants manufacture or produce protein in the shape of starch, albumen, sugar, etc., Avhich is animal food. Plants inhale carbonic acid gas and exhale oxygen; animals inhale oxygen and exhale carbonic acid; though Draper has discovered that, under certain circumstances, plants may exhale carbonic acid.