whirl in the innumerable myriads of living cells which constitute each tree, we should be stunned, as with the roar of a great city.'
"There is, however, this fundamental difference between plants and animals ; that while plants can manufacture fresh protoplasm out of mineral elements, animals, on the other hand, are obliged to procure it ready made, and in the long run depend upon plants. 'With this qualification it may be truly said that the acts of all living things are fundamentally one.'
"But this unity is not limited to action; Mr. Huxley maintains that it extends also to form:—
"'If a drop of blood be drawn by pricking one's finger, and viewed with proper precautions and under a sufficiently high microscopic power, there will be seen, among the innumerable multitude of little, circular, discoidal bodies, or corpuscles, which float in it and give it its color, a comparatively small number of colorless corpuscles, of somewhat larger size and very irregular shape. If the drop of blood be kept at the temperature of the body, these colorless corpuscles will be seen to exhibit a marvellous activity, changing their forms with great rapidity, drawing in and thrusting out prolongations of their substance, and creeping about as if they were independent organisms.
"'The substance, which is thus active, is a mass of protoplasm, and its activity differs in detail, rather than in principle, from that of the protoplasm of the nettle. Under sundry circumstances the corpuscle dies and becomes distended into a round mass, in the midst of which is seen a smaller spherical body, which existed, but was more or less hidden, in the living corpuscle, and is called its nucleus. Corpuscles of essentially similar structure are to be found in the skin, in the lining of the mouth, and scattered through the whole framework of the body. Nay, more; in the earliest condition of the human organism, in that state in which it has just become distinguishable from the egg in which it arises, it has nothing but an aggregation of such corpuscles, and every organ of the body was, once, no more than such an aggregation.
"'Thus a nucleated mass of protoplasm turns out to be what may be termed the structural unit of the human body. As a matter of fact, the body, in its earliest state, is a mere multiple of
