32 
SCHIZANTHUS PRIESTII. 
which he considers to be the elements of a diffused nervous system,, and he ascribes 
the movements of plants to their action. 
M. Marcet, of Geneva, after trying a series of experiments with mineral and 
vegetable poisons, concludes, — 
1st. That metallic poisons act upon vegetables nearly as they do upon animals ; 
they appear to be absorbed and carried into the different parts of a plant, altering 
and destroying the vessels by corrosive powers. 
2ndly. That vegetable poisons, especially those which have been proved to 
destroy animals by their action upon the nervous system, also cause the death of 
plants ; whence he infers that there exists in the latter a system of organs which is 
affected by poisons nearly as the nervous system of animals. 
These discoveries neutralise many, if not all, of the former definitions of plants. 
One of the ancient botanists defined a plant to be an animal fixed by means of a 
root. Jungius, who lived about the beginning of the seventeenth century, defined 
a plant to be a body possessing vitality, but without sensation, and fixed to a certain 
spot, from which it derived the nourishment necessary to the development of its 
parts and the re-production of its species. Linnaeus, in fixing the boundaries of the 
mineral, vegetable, and animal kingdoms, said, stones grow ; plants grow and live ; 
animals grow, live, and feel.” M. Bonnet, of Geneva, defined a plant to be an 
organised body, nourished by means of roots placed externally , an animal being an 
organised body nourished by means of roots (lacteals) placed internally. Hedwig 
considered that the re-productive organs of a plant, after having discharged their 
peculiar functions, uniformly decay and drop off, before the fruit has reached 
maturity, while those of the animal remain permanent, and perish only with 
individual itself. M. Mirbel has latterly introduced a criterion, founded on the 
character of the substances on which plants and animals feed. Plants feed upon 
unorganised substances, as earths, salts, water, or gases. Animals feed upon 
substances already organised, as vegetables, animals, or their products : but never 
wholly upon substances in an unorganised state. From this last definition, Mr. 
Keith deduces that a vegetable is an organised and living substance, springing 
from a seed or germ, which it again produces, and effecting the development of its 
parts by means of the intro-susception and assimilation of unorganised substances, 
which it derives from the atmosphere or from the soil in which it grows. An 
animal is an organised and living being, proceeding from an egg or embryo, which 
it again produces, and effecting the development of its parts by means of the 
intro-susception of organised substances, or their products. 
Irritability in some cases resides in the leaves, as in Dioncea , &c., and at other 
times in the flowers, as in the Schizantkus, Berberis, Opuntia Tuna, Aristolochia , 
Clematitis, fyc. in all which the stamina are so irritable, that if touched in certain 
parts they instantly start from their former positions, and striking their heads 
against their stigma, answer the end for which they were designed. - 
