lowest point, or when they cut away the whole loop, and form of it a separate kingdom — the Protista of Hæckel. The only objection to the latter is that the definition of this tertium quid from plant on the one hand and animal on the other is equally impracticable. One difficulty is removed only to have two in its place. The fact is, that a new article has recently been added to the scientific creed, -the essential oneness of the two kingdoms of organic nature. I crave your patience while I enter somewhat into particulars.

Not many years ago it was taught that plants and animals were composed of different materials: plants, of a chemical substance of three elements, carbon, hydrogen, and oxygen; animals of one of four elements, nitrogen being added to the other three. The plant substance, named cellulose, because it formed the cell-walls, was supposed to constitute the whole vegetable fabric. It was known that all plants produced nitrogenous matter in the form of a compound of four elements; but this was thought to be merely a contained product, in a structureless condition, and to be not so much essential to the plant's life as to that of the animals which the plants nourished. It was known to be struc

ture-building material for animals: it was not known to be essential plant-structure also. But it was soon ascertained that this quaternary matter of the animal body was chemically the same in the plant, was elaborated there, and only appropriated by the animal. Next it was found that it was physiologically and structurally the same in the plant, that it was the living part of the plant, that which manifested the life and did the work in vegetable as well as in animal organisms. This substance, which is manifold in its forms and protean in its transformations, has, in its state of living matter, one physiological name which has become familiar, that of protoplasm. The statement that "protoplasm is the physical basis of life" must be accepted as true. As Professor Allman puts it, "wherever there is life, from its lowest to its highest manifestations, there is protoplasm; wherever there is protoplasm, there too is life," or has been. The cellulose or solid material which composes the bulk of a tree or herb did not produce the protoplasm contained in its living parts, as was formerly supposed, but the protoplasm produced the cellulose: the semiliquid and mobile matter within produced the cell-walls which enclose it. The walls or solid

parts are to the protoplasm what the shell is to the oyster. The contents not only preceded the protective investment, but can exist and prosper apart from it, as many a mollusk does, as many a simple plant does throughout the earlier and most active period of its life. In· deed this slimy matter lives before and apart from any thing which can be called a living being. A formless, apparently diffluent and structureless mass is seen to exhibit the essential phenomena of life, to move, to feed, to grow, to multiply. We have spoken of beings so low in the scale that the individuals throughout their whole existence are not sufficiently specialized to be distinctively plant or animal: yet these are definite in form and fixed in phase, are individual beings, though we may not determine to which kingdom they belong. But there is life in simpler shape,

"If shape it might be called that shape has none,
Distinguishable in member, joint, or limb,"

there is vital activity in that which has not attained even the semblance of individuality. Little lumps of protoplasm are these, with outline in a state of perpetual change, divisible into two or three or more, or two or three com

bining into one mass, either way without hindering or altering their manifestations. This living matter-of which Bathybius, if there be a Bathybius, or if it be any thing more than protoplasm of sponges, is one example is said to have nothing more than molecular structure. It would be safer to say that the microscope has as yet revealed no organic structure.

The natural history of protoplasm has recently been well expounded by Professor Allman, late President of the British Association, a most judicious naturalist, of conservative tendency; and his address, which you have read or should read, saves me from further details, and enables me to proceed to other evidences of the substantial oneness of the two kingdoms of organic nature.

Cellulose makes up the bulk of a vegetable,. and was thought to be its true element. But it is now known to be not even peculiar to it: it enters largely into the fabric of certain animals, not of the very lowest grade. Starch was equally regarded as a purely and characteristically vegetable production; and its presence, in ambiguous cases, has been taken as a test. But it follows the example of cellulose. Being a prepared material from which cellulose