while, on the other hand, not only are these four ingredients sufficient of themselves to form a substance capable of living, but they actually do with very little (when any) foreign admixture, form all substances whatsoever that are ever found vivified. All such substances, he informs us, are but varieties of _protoplasm_, differing indeed from each other in texture, colour, and general appearance, even as a diamond differs from granite, yet all being equally protoplasm, just as a diamond and a block of granite are equally stones, or as heart of oak and the outer case of a nettle's sting are equally wood. The human ovum, he gives us to understand, is in its earliest stage but a single particle of protoplasm; the human foetus but an aggregation of such particles, variously modified; the human body perfectly matured, but a larger aggregation of such particles still further modified. He proceeds to point out, as following from these premises, that a solution of smelling salts, together with an infinitesimal quantity of certain other salts, contains all the elements that enter into the composition of protoplasm, and consequently of whatever substance the very highest animal requires for sustenance. He does not, however, leave us to suppose that any abundance of the fluid in question would avail aught to save a hungry creature of any sort from starving, but continues his exposition to the following effect. Not only is there no animal, there is not even any vegetable organism, to which the elements of food can serve as food, as long as they remain elementary. It is indispensable that hydrogen and oxygen should combine to form water, nitrogen and hydrogen to form ammonia, carbon and oxygen to form carbonic acid; and even then, even at a table groaning under whole hogsheads of these primitive compounds, there is no single animal that would not find itself at a Barmecide feast. There are many plants likewise, which in the midst of such uncongenial plenty would be equally without a drop to drink; but there are also multitudes of others which, without the aid of any more elaborated nutriment, would be able to grow into a million, nay million million fold of their original bulk. Provided there be in the seed or germ of any of these latter one single particle of living protoplasm to begin with, that single particle may convert into animated protoplasm an indefinite quantity of inanimate ammonia, carbonic acid, and water. The protoplasm thus created in the first instance, and created, let us suppose, in the form of a lichen or a fungus, is converted by decay into vegetable mould, in which grass may take root and grow, and which, in that case, will be converted into herbaceous protoplasm; which, being eaten by sheep or oxen, becomes ovine or bovine protoplasm, commonly called mutton or beef; which, again, being eaten by man, becomes human protoplasm, and, if eaten by a philosopher, becomes part of a mass of protoplasm capable of