INDIVIDUALITY, the quality of being individual: separate or distinct existence. There is some difference of opinion as to what constitutes individuality, the, discussion being principally confined to the domain of natural history. Some authorities regard the various organisms springing by buds from a single hydroid as an individual. Others again consider various parts of a tree to be individuals. The question cannot be settled without looking at it from two points of .view. In one sense all the organisms proceed ing from one egg may be considered as comprising one individual, being derived from one germ, the production of the zooids by budding being similar to the development of a stock by grafting; but similar only because, in grafting, a part of one individual, and not a germinal part, is inserted into another, and there proceeds to grow, as though the original plant extended itself. But in the budding of hydroids the different zooids thus produced exactly resemble each ether, depart from each other, and develop inde pendently into hydroids like their parent; and some may develop much more rapidly than others. The production of a zooid is more like original germination or ovum development than the growth and extension of a part of the common tissues of a parent. In one sense the new tree which has grown from the stock of another is a part of that tree; but in another, and probably a more exact sense, it is another and entirely inde pendent tree—a separate individual. A tree, taken as a whole, whether while putting out its leaves, or in bloom, or bearing ripe seed, is an individual, while each ripe seed may be regarded as potentially an individual. If it fall upon the earth and sprout it becomes an individual tree, like its parent. It might be said that the acorn does not become an individual in a strict sense until it becomes a tree; but it may be held logical to consider that it became an individual as soon as it became a perfectly developed seed.
If we do not look at the subject in this way we shall be obliged to regard all objects in nature as mere fragments of one great whole, which in a spiritual sense is true; but the application of metaphysical methods to natural science only leads to confusion. Each leaf of a plant iscertainly an individual leaf, but in a true sense it is not an individual, for it can have no independent existence; it is only a part of a compound organ of respiration of plant life, and may be compared to a pulmonary vesicle of the lung of an animal.
In the case of the Siamese twins, they are, doubtless, correctly regarded 113 two individuals, and yet iu so far as their livers, which seem to have been united, were really combined and performed their functions in union, they were not quite distinct individuals. They must have possessed individual minds, and, in the higher sense, were entirely distinct individuals. Other monsters have been born having two heads and only one body. It would not be logical to regard such, taken as a whole, as being distinct individuals, each brain being dependent upon a common body. In one sense the organism comprises two individuals, but in another it does not. If such a mon ster could live, the two brains could not be independent in function of each other. Individuality is, therefore, to a certain degree, a relative term, and the use of the term sometimes requires explanation. This is one of those questions in which is illustrated the dependence of physical upon metaphysical science.