40. What does the term Life stand for? What are the concrete significates of this abstract symbol? As before stated, it is sometimes a compendious shorthand for the special phenomena distinguishing living from non-living bodies; and sometimes it expresses not these observed phenomena, but their conditions of existence, which are by one school personified in an abstract and extra-organic cause. Thus the life of an animal, a man, or a nation, means--1°, the special manifestations of these organisms, and groups of organisms; or 2°, the causes which produce these manifestations. We are often misunderstood by others, and sometimes vague to ourselves, when we do not bear these two different meanings in view. It was probably some sense of this which made Aristotle distinguish Vitality from Life, as that of the one uniform cause separated from its multiple effects; it was certainly the motive of Fletcher, who thus expressly limits the meanings: “_Vitality_ or _Irritability_, the property which characterizes organized beings of being acted on by certain powers otherwise than either strictly mechanically or strictly chemically; _Life_, the sum of the actions of organized beings resulting directly from their vitality so acted on.”[10] Vitality and Life being thus discriminated as the statical and the dynamical aspects of the organism, we find in relation to the former two radically opposed conceptions: the metaphysiological or extra-organic, and the physiological or intra-organic. The first conceives Vitality to be a Vital Principle, or extra-organic agent, sometimes a soul, spirit, archæus, idea, and sometimes a force, which easily becomes translated into a property.