it is our clear duty to use the former, and no harm can accrue so long as we bear in mind that we are dealing with terms and symbols. In itself it is of little moment whether we express the phenomena of matter in terms of spirit or the phenomena of spirit in terms of matter." A remarkable declaration, certainly, to come from an eminent professor of physical science, the superior adaptation of which to train the mind to habits of precision is the continual boast of its friends. We shall have occasion, as we proceed, to notice the singular use of words by our author, and shall, perhaps, find that he has been led into some striking fallacies by it. We allude to it now that our readers may have it in mind as we advance in the examination of the argument.

Professor Huxley announces his subject as "Protoplasm," but as he supposes this term is not generally intelligible he translates it, for the benefit of the unscientific, into the phrase "Physical Basis of Life." We regard it as unfortunate that a term which has acquired a definite signification, should have been exchanged for such a phrase as "Physical Basis of Life," or that the writer had not at least explained what he means by this somewhat ambiguous expression. For instance, he nowhere tells us what he means by "life." He, indeed, states the common conception of life to be "something which works through matter, but is independent of it," leading us to suppose that he himself conceives of "life" as something different from this; but whether, in his view, life is something which does not work through matter, meaning something which has no connection with matter, or as something which is dependent on matter, we are not clearly informed. In the next line of his printed essay we find it stated that "life and matter are inseparably connected," which seems to be intelligible, and we understand him to hold that the stones have life, and even the "cooked mutton," about which he is so learned and witty, declaring that it is "competent to resume its old functions as matter of life," although now "dead."

He afterwards, however, speaks of "lifeless matter," that is matter which is not "inseparably connected with life," under which class he includes cooked mutton, but as he does not explain how the cooked mutton can be "lifeless" and yet have

power to do what he says it is competent to do, we are left in doubt as to his making any real distinction between the living and the lifeless. He seems here to think it of no importance what terminology he uses. So, too, "basis" is a word having a definite meaning as a foundation on which a superstructure, of life for instance, is or may be built, and we should suppose that to be its meaning here, but that we find Professor Huxley almost immediately using it as synonymous with "matter," as if he intended by it the material substance out of which life is made, and we finally conclude this latter to be his real meaning. If, however, Professor Huxley does not explain the expression, "Physical Basis of Life," he goes on to inform us what conclusion is suggested by it, viz: "that there is one kind of matter which is common to all living beings, and that their endless diversities are bound together by a physical unity." This statement is simple and definite, and we think we have arrived at the truth which this teacher is about to present to us, and we inquire is this the new philosophy which is to revolutionize the opinions of men? Is this the conclusion "shocking to common sense," by accepting which we are to be led away from heaven? Is this the foundation. for the somewhat glowing rhetoric with which Professor Huxley brings into one class the brightly colored lichen of the rock and the painter who strives to reproduce it on the canvass; the microscopic fungus and the gigantic Californian pine; the flower which adorns a girl's hair and the blood which courses through her veins ?

It is no new idea that there is one kind of matter common to all living beings and inanimate things as well. Chemistry long ago told us that all material substances may be resolved into a few simple elements. The experience of the world has shown from the first, that at death all living things are changed into their inanimate constituents. The oldest book we have teaches among its earliest utterances that man, the head of creation, was formed of the dust of the ground. We have no difficulty with this "conclusion" which the Professor announces. We accept it heartily. There is a sense in which all animals are "bound together in a physical unity," and in that sense we assent to the proposition; not meaning thereby that all

living things are parts of one vast material substance, or that they have all sprung from the same grain of matter; not asserting that there is no diversity; but such a unity as is indicated by the word of God, and by the experience of men coupled with the investigations of science.

Professor Huxley does not allow us to rest long on this proposition. He proceeds to develop his theory more in detail.

Before proceeding, however, to discuss his arguments, we will quote from his essay some passages which will serve to acquaint our readers with the facts on which these arguments

rest:

"You are doubtless aware that the common nettle owes its stinging property to the innumerable stiff and needle-like, though exquisitely delicate, hairs which cover its surface. Each stinging-needle tapers from a broad base to a slender summit, which, though rounded at the end, is of such microscopic fineness that it readily penetrates, and breaks off in the skin. The whole hair consists of a very delicate outer case of wood, closely applied to the inner surface of which is a layer of semi fluid matter, full of innumerable granules of extreme miuuteness. This semi-fluid lining is protoplasm, which thus constitutes a kind of bag, full of a limpid liquid, and roughly corresponding in form with the interior of the hair which it fills. When viewed with a sufficiently high magnifying power, the protoplasmic layer of the nettle hair is seen to be in a condition of unceasing activity. Local contractions of the whole thickness of its substance pass slowly and gradually from point to point, and give rise to the appearance of progressive waves, just as the bending of successive stalks of corn by a breeze produces the apparent billows of a corn-field. But, in addition to these movements, and independently of them, the granules are driven, in relatively rapid streams, through channels in the protoplasm which seem to have a considerable amount of persistence. Most commonly, the currents in adjacent parts of the protoplasm take similar directions; and thus, there is a general stream up one side of the hair and down the other. But this does not prevent the existence of partial currents which take different routes; and, sometimes, trains of granules may be seen coursing swiftly in opposite directions, within a twenty-thousandth of an inch of one another; while, occasionally, opposite streams come into direct collision, and after a longer or shorter struggle one predominates. The cause of these currents seems to lie in contractions of the protoplasm which bounds the channels in which they flow, but which are so minute that the best microscopes show only their effects, and not themselves."

"If a drop of blood be drawn by pricking one's finger, and viewed with prop er 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 marvelous activity, changing their forms with great raVOL. XXIX. 15

pidity, 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 frame work 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 is 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 the structural unit of the human body." 'Beast and fowl, reptile and fish, mollusk, worm and polype, are all composed of structural units of the same character, namely, masses of protoplasm with a nucleus."

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In these extracts we have all the facts which are essential to enable us to understand the arguments used by Professor Huxley to support his main proposition. Other facts we shall bring forward as it becomes necessary. His statement of a general unity he now develops as follows:

"I propose to demonstrate that a three-fold unity, namely, a unity of power or faculty, a unity of form, and a unity of substantial composition, pervades the whole living world."

Let us examine each of these propositions with the promised demonstation in order. First, a unity of power pervades the whole living world. Professor Huxley explains that these powers may be different in degree, but claims that they are similar in kind. The proposition then, is, that the same kind of power pervades all living things. The demonstration is as follows: "Either they (the powers of all living things) are immediately directed to the maintenance and development of the body, or they effect transitory changes in the relative positions of parts of the body, or they tend towards a continuance of the species." Granting all this to be true, the demonstration is not complete. The argument is that because, for instance, the body of a plant is maintained and developed by "a power," and the body of an animal is maintained and developed by "a power," therefore these powers are of the same kind. But this reasoning does not go very far to establish the proposition. Even if we admit that the results of the

two powers are the same, that is, that the body of the plant and the animal are the same, which is certainly not a self-evident truth, it does not necessarily follow that the powers from which each are derived are the same. In the inanimate world the same result may be produced in different ways, by different powers. How does it appear that the same is not the case in the living world? That an accomplished result is a certain indicator of the kind of power which produced it, is not an axiom, and if it is true, its truth needs to be shown. But Professor Huxley assumes it. He brings no evidence to show that the processes which tend to the maintenance and development of the body of the plant are directed by the same kind of power as those which tend to the maintenance and development of the body of the animal. This unity of power is asserted-assumed; not proved nor demonstrated.

If we suppose that by this proposition Professor Huxley means that as the powers of all living things reside in the protoplasms, there is a unity of power, or the same kind of power in the protoplasms, no proof is adduced of this. Let us enquire, however, what the facts, as he has given them, teach on this subject. Do they show that the powers of the animal and vegetable protoplasms are of the same kind? The protoplasm of the animal has no power to assimilate mineral matter, or, in the language of Professor Huxley, "to manufacture new protoplasm out of mineral compounds." "A solution," he says, "of smelling salts in water, with an infinitesimal proportion of some other saline matters, contains all the elementary bodies which enter into protoplasm; but as I need hardly say, a hogshead of that fluid would not keep a hungry man from starving, nor would it save any animal whatever from a like fate." If, however, the animal cannot, the vegetable protoplasm can, derive nourishment from mineral matter. "The fluid," he continues, "which offers such a barmecide feast to the animal, is a table richly spread to multitudes of plants." This "striking difference," as Professor Huxley himself calls it, interferes materially with the truth of the proposition, that "a unity of power pervades the whole living world," and perhaps ends the discussion on this point. We observe, however, another "striking difference" between