- In the Hydromedusae the medusa-individual occurs, as already stated, in one of two conditions, either as an independent organism leading a true life c2 a2 in the open seas, or as a subordinate individuality in the hydroid c colony, from which it is never set free; it then becomes a mere reproductive appendage or gono- phore, losing suc FIG.
It can only be understood by subordinating the mechanical conception to the vital, by conceiving the world as one organism animated by a spiritual principle or intelligence (Weltseele).
Th~ phenomenon of irritability here concerned is well shown in certain cases where a parasitic organism gains access to a celle.g.
It is not true, for example, that a fish is a reptile arrested in its development, or that a reptile was ever a fish; but it is true that the reptile embryo, at one stage of its development, is an organism which, if it had an independent existence, must be classified among fishes; and all the organs of the reptile pass, in the course of their development, through conditions which are closely analogous to those which are permanent in some fishes.
No biological generalization rests on a wider series of observations, or has been subjected to a more critical scrutiny than that every living organism has come into existence from a living portion or portions of a pre-existing organism.
Homogenesis means simply that such organism comes into existence directly from a parent organism of the same race, and hence of the same species, sub-species, genus and so forth.
The term Anatomy, originally employed in biological science to denote a description of the facts of structure revealed on cutting up an organism, whether with or without the aid of lenses for the purposes of magnification, is restricted in the present article, in accordance with a common modern use, to those facts of internal structure not concerned with the constitution of the individual cell, the structural unit of which the plant is composed.
In spite of the statement that the nature of the organism is the most important factor in variation, the tendency amongst evolutionists has been to take much more account of the influence of external conditions.
AdaptationThe morphological and physiological differentiation of the plant-body has, so far, been attributed to (I) the nature of the organism, that is to its inherent tendency towards higher organization, and (2) to the indefinite results of the external conditions acting as a stimulus which excites the organism to variation, but does not direct the course of variation.
"Just as a steamengine," he says in Kraft and Stoff (7th ed., p. 130), "produces motion, so the intricate organic complex of force-bearing substance in an animal organism produces a total sum of certain effects, which, when bound together in a unity, are called by us mind, soul, thought."
This has taken the form of inoculating the soil with the particular organism required by the particular kind of leguminous crop. To this end the endeavour has been made to produce preparations which shall contain in portable form the organisms required by the several plants, and though, as yet, it can hardly be claimed that they have been generally successful, the work done justifies hopes that the problem will eventually be solved in a practical direction.
(2) That the fixation of the gas is carried out by the fungal organism either in the soil or in the plant, and the nitrogenous substance so produced is absorbed by the organism, which is in turn consumed by the green plant.