which appears upon decaying vegetable substances, and in one of its forms is common upon the surfaces of tan-pits. In this condition it is, to all intents and purposes, a fungus, and formerly was always regarded as such; but the remarkable investigations of De Bary have shown that, in another condition, the Æthalium is an actively locomotive creature, and takes in solid matters, upon which, apparently, it feeds, thus exhibiting the most characteristic features of animality. Is this a plant? or is it an animal? Is it both? or is it neither? Some decide in favor of the last supposition, and establish an intermediate kingdom, a sort of biological No-Man's Land for all these questionable forms. But, as it is admittedly impossible to draw any distinct boundary line between this no-man's land and the vegetable world on the one hand, or the animal on the other, it appears to me that this proceeding merely doubles the difficulty which, before, was single.
"'Protoplasm, simple or nucleated is the formal basis of all life. It is the clay of the potter, which, bake it and paint it as he will, remains clay, separated by artifice, and not by nature, from the commonest brick or sun-dried clod.'
"The transformations of protoplasm, in their practical aspect, are thus neatly illustrated by the Professor:—
"'In the wonderful story of the "Peau de Chagrin," the hero becomes possessed of a magical wild ass's skin, which yields him the means of gratifying all his wishes. But its surface represents the duration of the proprietor's life; and for every satisfied desire the skin shrinks in proportion to the intensity of fruition, until at length life and the last hand-breadth of the peau de chagrin disappear with the gratification of a last wish.
"'Balzac's studies had led him over a wide range of thought and speculation, and his shadowing forth of physiological truth in this strange story may have been intentional. At any rate, the matter of life is a veritable peau de chagrin, and for every vital act it is somewhat the smaller. All work implies waste, and the work of life results, directly or indirectly, in the waste of protoplasm.
"'Every word uttered by a speaker costs him some physical loss: and, in the strictest sense, he burns that others may have light,—so much eloquence, so much of his body resolved into carbonic acid, water, and urea. It is clear that this process of expenditure cannot go on forever. But, happily, the protoplasmic peau de
