Materialism is obviously unproved so long as life is not shown to be a property or an effect of matter. Life has certainly not yet been shown to be either the one or the other. "The present state of knowledge," says Professor Huxley, in his article on "Biology," in the 'Encyclopædia Britannica,' "furnishes us with no link between the living and the not-living."

Numerous definitions have been given of life, but even the best of these definitions appear to be seriously defective. Biology has not yet succeeded in forming a precise and accurate notion of what life is. Perhaps we must be content to understand by it, so far as it falls under the consideration of physical science, the cause of the direction and co-ordination of the movements or actions characteristic of bioplasmic matter.

Mr Herbert Spencer (Principles of Biology, vol. i. pp. 60, 61) has well indicated the unsatisfactoriness of the definition of Schelling-"Life is the tendency to individuation;" of that of Richerand-"Life is a collection of phenomena which succeed each other during a limited time in an organised body;" of that of De Blainville— "Life is the twofold internal movement of composition and decomposition, at once general and continuous;" and of that of Lewes "Life is a series of definite and successive changes, both of structure and composition, which take place within an individual without destroying its identity." Mr Spencer has also laboured to provide a better definition; and some writers suppose that his suc

cess has been almost complete. Thus Professor Bain (Logic, Part II. p. 258) says: "Choosing assimilation as a characteristic fact of bodily life, and reasoning as an example of mental life, and contrasting both with the characters of dead matter, Mr Herbert Spencer arrives at the following highly complex definition: 1. Life contains a process or processes of change. 2. The change is not a simple or individual act, but a series or succession of changes. 3. Life involves a plurality of simultaneous as well as successive changes. 4. The changes are heterogeneous, or various in character. 5. The various changes all combine to a definite result. 6. Finally, the changes are in correspondence with external coexistences and sequences. In sum: Life is a set of changes, simultaneous and successive, combined to a definite result, and in correspondence with external circumstances. Or, in a briefer form, Life is the continuous adjustment of internal relations to external relations. So carefully has the comparison been conducted, that no exception could be taken to any part of this definition. Every one of the particulars occurs in all living bodies, and in no kind of dead matter." This estimate I cannot but regard as much too favourable. There is not a single particular in Mr Spencer's definition which is not as characteristic of the action of a watch as of the life of a plant or animal. His so-called definition is a sort of expression of what is common to the manifestations of machinery, life, and mind; but it gives us no information either as to what mechanism, life, and thought are, or as to how we are to distinguish them. It professes to be a definition of life, but really leaves life wholly out of account, in order to facilitate the work incumbent on a materialistic philosophy. In fact, Mr Spencer has not

sought a definition in a rational way. It is vain to attempt to define life by generalising its own effects. Biologists of all schools have abandoned this method of procedure as utterly unscientific, and now seek to accomplish their aim by the experimental study of life in its simplest forms. The true method to be followed has perhaps never been so clearly traced as by the illustrious French physiologist recently deceased, M. Claude Bernard, in his 'Leçons sur phénomènes de la vie communs aux animaux et aux vegetaux' (1878). M. Bernard has been often claimed as a materialist and as a positivist; but, in reality, his profound physiological science led him to results fatal both to materialism and to positivism; and a careful study of the work mentioned will render impossible the acceptance of all definitions of the kind to which that of Mr Spencer belongs-definitions based on a merely outside or superficial view of the manifestations of life.

Science is not only entitled but bound to trace the stream of life back as far as it can. The hypothesis of Mr Darwin, that all terrestrial organisms may have originated in a single primordial germ, which was produced when the earth was fitted to receive it, is a perfectly legitimate scientific hypothesis, although, of course, it should not be believed until it is proved. Equally legitimate in a scientific point of view is the hypothesis that life did not originate on this earth, but has come to it from remote and older worlds. This hypothesis has been presented in two forms.

1. According to M. Edgar Quinet (La Création, T. ii. L. xi. ch. ii.), Professor Preyer (Deutsche Rundschau, Heft 7), and Dr O. Zacharias (Athenæum, Bd. i. pp. 413-429), life is not fixed and limited to certain points.

of space or periods of time; is of a cosmical, not of a terrestrial nature; has been coeval with the universe; has passed from nebula to nebula; and has been derived by the earth from the mass whence it was itself detached. Professor Preyer, indeed, imagines that living and organic existences preceded and deposited all dead and inorganic matter. Even when not urged in this burlesque shape, the view that life has come to the earth. from the mass whence it was severed seems untenable. Contemporary science is very far astray if our planet has not passed through a condition in which its temperature must have been fatal to all life.

2. According to Sir William Thomson (Address to the British Association in 1871), and Helmholtz (Preface to the second part of the first volume of the German translation of Thomson and Tait's 'Natural Philosophy'), life may have been carried to our earth in the clefts or crevices of meteoric stones-the fragments of shattered worlds, once rich in vital forms. The attempt of Zöllner, in his work 'On Comets,' to show that this conception is essentially unscientific, is extremely weak. Of course the hypothesis does not explain the origin of life, but only suggests that its origin may have to be sought much further away than where scientists are looking for it. This, however, is all that it proposes to do. It does not profess, at least as stated by Sir William Thomson, to be a theory of the origin of life, but only a possible way of accounting for the origin of terrestrial life. The objection that the heat of the meteoric stones must have been incompatible with their conveyance of life does not seem to have been substantiated. Apparently the heat in a deep crevice of a large meteorite would not be so intense as to destroy a living germ.

But although the hypothesis is quite scientific in its nature, and has not been shown to involve any physical impossibility, no positive evidence has been produced on behalf of it.

Many anti-theists in the present day feel constrained by their inability to account, on purely physical principles, for the life associated with matter, to maintain its eternity. Thus some of those who trace it in the way which has just been mentioned from our world to others, forthwith conclude that it is coeval with matter, and that both matter and life must be regarded as unoriginated. They overlook that the life under consideration is life which implies material conditions, and these of a kind not necessarily involved in the very constitution of matter; that it could only appear when the universe was in a certain state of development; that it could not have existed, for example, in a nebula. To trace life from world to world can never show it to be eternal, if it can appear in no world which has not passed through certain stages before reaching the condition in which alone life can be realised. Besides, the assumption that matter is eternal is unscientific and arbitrary.

The old hypothesis of a world-soul has also recently been revived in various forms, and presented as an explanation of the origination of life in individual organisms. In this way materialism loses itself in pantheism, while in no form is the hypothesis of a world-soul demanded or supported by critically ascertained and scientifically interpreted facts.

Then there are speculators who would efface the distinction between the living and the dead, the organic and the inorganic, by ascribing to every atom of matter a small portion or faint degree of life. Those who pro