We must bear in mind that every organized being now in existence represents the last link of an inconceivably long series of organisms, which come down in a direct line of descent, and of which each has inherited a part of the acquired characteristics of its predecessor. Everything, furthermore, points in the direction of our believing that at the beginning of this chain there existed an organism of the very simplest kind, something, in fact, like those which we call organized germs. The chain of living beings thus appears to be the magnificent achievement of the reproductive power of the original organic structure from which they have all descended. As this subdivided itself and transmitted its characteristics1 to its descendants, these acquired new ones, and in their turn transmitted them-all new germs transmitting the chief part of what had happened to their predecessors, while the remaining part lapsed out of their memory, circumstances not stimulating it to reproduce itself.

An organized being, therefore, stands before us a product of the unconscious memory of organized matter, which, ever increasing and ever dividing itself, ever assimilating new matter and returning it in changed shape to the inorganic world, ever receiving some new thing into its memory, and transmitting its acquisitions by the way of reproduction, grows continually richer and richer the longer it lives.

Thus regarded, the development of one of the more highly organized animals represents a continuous series of organized recollections concerning the past development of the great chain of living forms, the last link of which stands before us in the particular animal we may

1 "Characteristics" must, I imagine, according to Professor Hering, resolve themselves ultimately into "vibrations," for the characteristics depend upon the character of the vibrations.

be considering. As a complicated perception may arise by means of a rapid and superficial reproduction of long and laboriously practised brain processes, so a germ in the course of its development hurries through a series of phases, hinting at them only. Often and long foreshadowed in theories of varied characters, this conception has only now found correct exposition from a naturalist of our own time.1 For Truth hides herself under many disguises from those who seek her, but in the end stands unveiled before the eyes of him whom she has chosen.

Not only is there a reproduction of form, outward and inner conformation of body, organs, and cells, but the habitual actions of the parent are also reproduced. The chicken on emerging from the eggshell runs off as its mother ran off before it; yet what an extraordinary complication of emotions and sensations is necessary in order to preserve equilibrium in running. Surely the supposition of an inborn capacity for the reproduction of these intricate actions can alone explain the facts. As habitual practice becomes a second nature to the individual during his single lifetime, so the often-repeated action of each generation becomes a second nature to the race.

The chicken not only displays great dexterity in the performance of movements for the effecting of which it has an innate capacity, but it exhibits also a tolerably high perceptive power. It immediately picks up any grain that may be thrown to it. Yet, in order to do this, more is wanted than a mere visual perception of the grains; there must be an accurate apprehension of the direction and distance of the precise spot in which each

'Professor Hartog tells me that this probably refers to Fritz Müller's formulation of the "recapitulation process" in Falls for Darwin, English edition (1869), p. 114.-R.A.S.

grain is lying, and there must be no less accuracy in the adjustment of the movements of the head and of the whole body. The chicken cannot have gained experience in these respects while it was still in the egg. It gained it rather from the thousands of thousands of beings that have lived before it, and from which it is directly descended.

The memory of organized substance displays itself here in the most surprising fashion. The gentle stimulus of the light proceeding from the grain that affects the retina of the chicken,' gives occasion for the reproduction of a many-linked chain of sensations, perceptions, and emotions, which were never yet brought together in the case of the individual before us. We are accustomed to regard these surprising performances of animals as manifestations of what we call instinct, and the mysticism of natural philosophy has ever shown a predilection for this theme; but if we regard instinct as the outcome of the memory or reproductive power of organized substance, and if we ascribe a memory to the race as we already ascribe it to the individual, then instinct becomes at once intelligible, and the physiologist at the same time finds a point of contact which will bring it into connection with the great series of facts indicated above as phenomena of the reproductive faculty. Here, then, we have a physical explanation which has not, indeed, been given yet, but the time for which appears to be rapidly approaching.

When, in accordance with its instinct, the caterpillar becomes a chrysalis, or the bird builds its nest, or the

1 This is the passage which makes me suppose Professor Hering to mean that vibrations from exterior objects run into vibrations already existing within the living body, and that the accession to power thus derived is his key to an explanation of the physical basis of action.

bee its cell, these creatures act consciously and not as blind machines. They know how to vary their proceedings within certain limits in conformity with altered circumstances, and they are thus liable to make mistakes. They feel pleasure when their work advances and pain if it is hindered; they learn by the experience thus acquired, and build on a second occasion better than on the first; but that even in the outset they hit so readily upon the most judicious way of achieving their purpose, and that their movements adapt themselves so admirably and automatically to the end they have in view-surely this is owing to the inherited acquisitions of the memory of their nerve substance, which requires but a touch and it will fall at once to the most appropriate kind of activity, thinking always, and directly, of whatever it is that may be wanted.

Man can readily acquire surprising kinds of dexterity if he confines his attention to their acquisition. Specialization is the mother of proficiency. He who marvels at the skill with which the spider weaves her web should bear in mind that she did not learn her art all on a sudden, but that innumerable generations of spiders acquired it toilsomely and step by step-this being about all that, as a general rule, they did acquire. Man took to bows and arrows if his nets failed him-the spider Starved. Thus we see the body and-what most concerns us-the whole nervous system of the new-born animal constructed beforehand, and, as it were, ready attuned for intercourse with the outside world in which it is about to play its part, by means of its tendency to respond to external stimuli in the same manner as it has often heretofore responded in the persons of its ancestors.

We naturally ask whether the brain and nervous system of the human infant are subjected to the principles we have laid down above? Man certainly finds

it difficult to acquire arts of which the lower animals are born masters; but the brain of man at birth is much farther from its highest development than is the brain of an animal. It not only grows for a longer time, but it becomes stronger than that of other living beings. The brain of man may be said to be exceptionally young at birth. The lower animal is born precocious, and acts precociously; it resembles those infant prodigies whose brain, as it were, is born old into the world, but who, in spite of, or rather in addition to, their rich endowment at birth, in after life develop as much mental power as others who were less splendidly furnished to Start with, but born with greater freshness of youth. Man's brain, and indeed his whole body, affords greater scope for individuality, inasmuch as a relatively greater part of it is of post-natal growth. It develops under the influence of impressions made by the environment upon its senses, and thus makes its acquisitions in a more special and individual manner, whereas the animal receives them ready made, and of a more final, Stereotyped character.

Nevertheless, it is plain we must ascribe both to the brain and body of the new-born infant a far-reaching power of remembering or reproducing things which have already come to their development thousands of times over in the persons of its ancestors. It is in virtue of this that it acquires proficiency in the actions necessary for its existence-so far as it was not already at birth proficient in them-much more quickly and easily than would be otherwise possible; but what we call instinct in the case of animals takes in man the looser form of aptitude, talent, and genius. Granted that

1 I interpret this: "There are fewer vibrations persistent within the bodies of the lower animals; those that there are, therefore, are stronger and more capable of generating action or upsetting