PARTICIPLE. See GRAIRMAR. PARTICLE, in physiology, the minute part of a body, an assemblage of which constitute all natural bodies. See Aram CAL philosophy.
It is the various arrangement and tex ture of these particles, with the differ ence of cohesion, &c. that constitute the various kinds of bodies. The smallest particles cohere with the strongest at traction, and compose bigger particles of weaker cohesion, and many of these co hering compose bigger particles, whose vigour is still weaker ; and hereupon the operations in chemistry, and the colours of natural bodies depend, and which, by cohering, compose bodies of sensible bulk. The cohesion of the particles of matter, the Epicureans imagined, was ef fected by the means of hooked atoms ; the Aristotelians, by rest ; but Sir Isaac Newton spews, that it is done by means of a certain power, whereby the particles mutually attract and tend towards each other. By this attraction of the particles, he shews that most of the phenomena of the lesser bodies are affected, as those of the heavenly bodies are, by the attraction of gravity.
In investigating the actions exerted be tween minute particles of matter, we must distinguish them as acted upon by the force of aggregation, or the force of chemical affinity : hence the distinction between the integrant and constituent particles of bodies. The constituent parts
are substances differing in their nature from each other, and from the substance which they form. The integrant parts are precisely similar to each other, and to the general mass which is composed by their union, or, in other words, they are the smallest particles into which a substance can be resolved without de composition ; while decomposition is al ways implied in the division of a body in to its constituent particles. The integrant parts are united by the force of aggrega tion, the constituent parts by chemical af finity. Hence chemists say that simple bodies consist entirely of integrant parts, all their particles being alike in their pro perties. But compounds may be consider ed as consisting both of integrant and constituent parts ; and it has been sup posed, that when an attraction is exerted between two compound substances, it is between their integrant parts, not their constituent principles, and that it is the combination of the former which constitutes the substance formed by their union.