Thus the idea of a limit is one around which evolution centres, in its widest as well as in its narrowest sphere.

And again in the same relation, the idea of a limit is equally suggested by the phenomena of force. Entirely unreconcilable with any complete dynamic theory is the idea of permanently fixed centres of force-any inherent powers. Gravity, for instance, refuses to be correlated with other forces; it remains as a permanent stumblingblock. What we rationally demand is an ever-current force always equal in amount, but never traceable to a final home:—a force which we might trace back and back under shifting forms indefinitely. Nay, this doubtless is the true theory of force; the mind can never be at rest under the incubus of supposed fixed centres, howsoever imagined, beyond or before which force is not. These fixed centres, these apparent primary foci of force, how then do they arise? Clearly by a limit. Limit force in time, and the phenomenon of "centres" of force is given.1

But to descend to regions less remote. The influence of this relation to a limit is visible in other phenomena

in thought; since unlimited space is inconceivable. All finite forms of the homogeneous-all forms of which we can know or conceive-must inevitably lapse into heterogeneity." But is it not remarkable that Mr. Spencer should make representability in thought a condition of his postulate, when he has himself taken so much pains to show that matter and force and motion are themselves not representable in thought? He says, for instance, p. 61: "It is impossible to form any idea of force in itself, (and) it is equally impossible to comprehend either its mode of exercise or its law of variation." It would appear surely that the starting-point at which Mr. Spencer legitimately found himself, was not a limited, but an unlimited homogeneity, in which, therefore, no evolution would occur, and that the one condition required to establish the whole process was precisely that of a limit-the very conception which we have found to constitute the starting-point of that new evolution upon the old, the organic world. The coincidence here seems striking.

1 And since "matter" is resolved into "centres of force," do we not, though somewhat vaguely, seem to trace matter to a limit?

belonging to the organic body, besides those before referred to. Its effect may be traced in the progressive increase in the amount and complexity of life. Upon the evolution theory the organic world has grown up out of the inorganic; that is, more and more force has assumed the vital form, and become expended in producing that unstable union of certain molecules which constitutes matter organic. At the same time, the forms into which this matter is built up assume more and more complexity of structure, and exhibit an increasing intensity of force. A limit is the general idea to which these phenomena point. That occurs in respect to the organic world which occurs when a fluid is pressed into a space from which there is no proportionate egress. There arises a continually heightening tension. The force being retained, and, as it were, turned inward on itself, becomes more intense. Possibly we may witness the results of this process in the highly complex structure of the organic molecules and the successive stages in which their decomposition takes place. None but the simplest organic substances are resolved directly into the ultimate chemical compounds. Almost all of them, in their fall from their unstable equilibrium, sink by successive slips, each containing less force than the preceding. In this complex structure and manifold process of decomposition, do we not see evidence of a complex process of upbuilding-successive impulses of force applied to the same molecules ?

If we turn from development of force to that of form, the same view recurs. Without reference to the constant tendency to increase of organic matter, and a resistance to its mere expansion, the extremely involved and, as it were, convoluted structure of the higher animals, can hardly be explained. Mere modifications by external

circumstances have no adaptation to make life more, though they may tend to alter its distribution; and simple differentiations and integrations do not account for the immense concentration of structure as well as force, the compressed and implicated variety of parts, which is characteristic of the more developed organisms. The general conception, which, as it seems to us, should be applied to the evolution of life, is one which recognises a pressure of the natural forces tending to give rise to the organic state of matter, and a constant resistance under which this process is carried on, leading to a higher tension of the force, and a more involved structure in the forms in which it is exhibited. This view furnishes also a partial justification of the otherwise untenable doctrine of an inherent tendency in life to progress. There is not an inherent tendency; but there is, apart from changing circumstances, an external constraint.

This pressure from without, arising from increase of the vital form of force, Mr. Spencer does not expressly note as bearing on evolution; nor does it appear to us that he assigns it even by implication a due place. Without it, the causes he assigns for evolution appear insufficient to bear the weight which rests on them. Adaptations do not alter totals. It is possible that he may design to make more reference to phenomena of this class in the succeeding volume, to which the discussion of individual structure is deferred; but it seems to us that they should find a place in the treatment of the general doctrine of evolution. Nature becoming organic -that being so far the direction of least resistance for her force-we believe is the great element which lies at the root of the whole process; nature becoming organic under limit.

And this balance of vital action and limit or control,

2 B

again, has the most striking illustration in the life of the individual organism; in which the whole nutrition and every function seem to be thus held in check, a special nervous organisation existing for this very end :which organisation itself, may we not say in accordance with Mr. Spencer's own views, is but the specialisation of an universal function in the organic world? But into this point and many others equally full of interest which press upon us, we have not space to enter now. It is with regret we leave so great a topic so scantily treated, and see our task cut off at its commencement; but we hope to resume it at no very distant day.

Biol.

Stutrition. Chem.-27.

Isecom portion

ON THE RELATION BETWEEN CHEMICAL
DECOMPOSITION AND NUTRITION.

XXVI.

(1862.)

My attention has been drawn to the question which heads this paper by my having become unwillingly involved in a controversy as to the origination of the view that the motor power in nutrition is chemical decomposition. Dr. Waters, of St. Louis, in America, on the one hand, claims to be the first propounder of this thought, and Dr. Freke, of Dublin, on the other, affirms his priority. Between them I am not competent to decide, though I am of opinion that both claims are practically just; Dr. Waters' statement being full and complete, but later; Dr. Freke's being earlier, but more indistinct, and perhaps capable of more than one interpretation.1

Dr. Freke says, “We find the living atom has imparted its organic properties to the inorganic matter, and in parting therewith has itself become inorganic." Dr. Waters, and others after him, trace out in express dynamic terms the process as they apprehend it; namely, that in the decay of one portion of organic matter force is set free, which acts as the "organising" force of other matter, either causing it to become organic (having previously not been so), or raising it from a lower to a higher vital

1 "On the Origin of Species by means of Organic Affinity." By H. Freke, M.D., &c. London: Longmans. 1861. P. 48.