VI.

THE UNCONSCIOUS IN THE REPARATIVE POWER OF NATURE.

WHEN the nest of the bird, the web of the spider, the cocoon of the caterpillar, the shell of the snail are injured,when the bird is stripped of a portion of its feathery robe,— the sufferers repair the loss which may imperil or impede their future existence. We have already seen that some of these phenomena must be ascribed to instinct, and can we fail to perceive the striking analogy of the other cases? We have seen that there is an unconscious idea of purpose, which, united with Will, dictates the conscious willing of the means to attain it; and are we to doubt that we have to do with the same thing, when the sphere of influence is no longer external, but the body itself, since we are not able to draw the line where the body proper begins and ends, as in the cocoon of the caterpillar, the shell of the snail, the feather-garment of the bird, or between excretion and secretion? If we deprive the polype of its tentacles or the worm of its head, the creature must die for want of food; and if the animal replaces the tentacles or the head and continues to live, can anything but the unconscious idea of their indispensableness be the fundamental cause of the restoration? Let it not be replied that the difference between instinct and the vis medicatrix lies in this, that in the former case the perceiving and willing of the means are, at any rate, conscious, but in the latter case these also are unconscious. For after the discussion on the independence of the lower nerve-centres, it cannot be doubted that the willing of the means may very well somehow and

somewhere reach the stage of consciousness in the lower nerve-centres, e.g., the small ganglionic cells, from which the sympathetic nerve-fibres which regulate nutrition arise, even if the chief centre of the animal knows nothing at all about it. On the other hand, no one will confidently decide, whether and how far in the lower animals in the case of instinct even the willing of the means is a conscious act.

Let us now look a little closer at the effects of the vis medicatrix. In the case of the Hydræ every part of the mass is replaced, so that a new animal is formed out of each piece, whether the division be transverse or longitudinal, or the creature be even cut into shreds. Among the Planariæ every segment, if it only amounts to one-tenth or one-eighth of the whole body, becomes a fresh animal. Among the Annelids or worms restoration follows only after transverse section, when head or tail is always regenerated. In some cases the animal may be cut into pieces, and yet each single piece develops into a perfect example of its kind. It seems here clear enough that if, after any one of these indefinitely numerous sections, the separated part always furnishes a specimen manifesting the typical idea of its kind, this effect cannot be due to a dead causality, but the type-form must be present in each piece of the animal. But an IDEA can only exist either realiter in its external manifestation as realised idea, or idealiter so far as it takes the form of mental picture, and in and through the presentative act. Hence every fragment of the animal > must have the unconscious image of the type according to which it accomplishes this regeneration; just as the bee before the construction of its first cell, and without ever having seen the like, carries in itself the unconscious representation of the hexagonal cell, accurate to half an angular minute, or as every bird must unconsciously have an idea of the form of the nest and mode of song characteristic of its species, before it has had any experience of the same. And observing the process of regeneration, e.g., of

a divided earthworm, a white bud may be seen sprouting at the cut part, which gradually becomes larger, then acquires narrow, closely packed rings, expanding on all sides, and contains prolongations of the digestive canal, the vascular system, and the ganglionic cord. It requires a strong faith to suppose that the nature of the exudation at the wounded part and the vicinity of the corresponding organs are sufficient to bring about a further growth of the animal. But when one sees how from two similar cut surfaces, separated by several rings, there is formed on the one side the head with its special organs, on the other the tail with its organs, and with organs too which have nothing at all analogous in the remaining portion of the trunk, the assumption of a dead causality, of a material mechanism without an ideal factor, becomes a sheer impossibility.

In addition to this there are various secondary circumstances, which most clearly prove that the idea of what must be executed in the special case to realise the type is the originally determining element in these events. If the animal is not full-grown, and a part of it be violently removed, the regenerated part does not correspond to the former state of the animal, but is constituted as such part would have been had the normal process of development never been interrupted. This may be seen if the leg of a young salamander or the tail of a tadpole be cut off. Somewhat similar is the case of the horns of the stag, which are annually renewed as long as the youthful vigour of the animal remains; but when the development of the organism has reached its highest point and the vigour declines, the last pair of horns either remains till death, or the pair annually reproduced becomes in extreme age shorter and simpler.

Further, the force directed to this restoration of a part is greater the more important such part is for the continued existence of the animal: thus, e.g., according to Spallanzani, worms regenerate their heads before their tails, and in

VOL. I.

K

fishes the restoration of the amputated fins takes place in the order of their importance as motor organs; thus the caudal fins first, then the pectoral and ventral, and lastly the dorsal fins. Should the force, or more accurately the power, of the unconscious will in moulding its material and the external circumstances be insufficient for the regeneration of a part in the normal way, still the type of the class always gleams through the malformations which then arise. Thus, e.g., if only one tentacle instead of two grows again on a snail's head which has been cut off, this one has two eyes, and men who have lost one joint of a finger sometimes have a nail growing on the second. The more a part is exposed to injury, the more easily is it regenerated. Thus, e.g., the rays of the Asterias, the legs of spiders, the tentacles and antennæ of snails and beetles, the tails of lizards, possess a considerable regenerative power on account of their liability to injury. For the most part, it is some special joint from which the regeneration most easily proceeds, in which case the connected limb is extremely fragile; and if injury occurs anywhere else, an additional limb is frequently thrown off at that spot. Crabs, for example, do this. Spiders likewise free themselves at the cost of a leg when they find it grasped or compressed; but if the animal be held fast whilst the leg is squeezed, it cannot afterwards thus unceremoniously throw off the same, but it first entangles the leg in its web, then propels itself with the other legs, and in this way wrenches it off. This is manifestly instinct; and when the crab spontaneously throws off the injured leg, is that to be called something fundamentally different from instinct? And yet rejection of the injured limb is merely the first act of restoration. Still more wonderful. is the instinct of the Holothuria which live in the Philippine Islands of the South Sea. These devour coral sand, and if they be taken from their native haunts and transferred to clear sea-water, they of their own accord eject from the anus the intestinal canal, with the branchia and

all other organs connected therewith, in order to form new viscera more in harmony with the altered medium. (A Holothuria burdened with needles or knives literally jumps out of its skin, rejecting it without in any way injuring its interior.)

The higher we ascend in the animal scale, the less potent, as a rule, becomes the vis medicatrix, being least influential in man. As long, therefore, as human physiology was exclusively studied, it was possible for the error to arise that a merely material mechanism produces remedial effects; but as anatomy first began to yield important results when it was studied comparatively, and psychology is just beginning to afford true enlightenment through a similar procedure, so in physiology only comparative investigation can give genuine insight. But when we have once got on the right track through a clear understanding of relations in the case of the lower animals, it will not be difficult to recognise this view also as the only possible one in the higher stages of organisation.

The reasons for the limitation of the vis medicatrix in the higher animal classes are partly internal, partly external. The inmost and deepest ground is that the organising force turns always more and more away from the outworks, and bends its whole energy to reach the final goal of all organisation, the organ of consciousness, in order to raise this to even higher perfection. The external grounds are that the organs of the higher animal classes are more solid, and also, in consequence of the mode of life of these creatures, are much less liable to fracture and mutilation, but at the most are exposed to wounds and injuries, for the majority of which the healing power of Nature is sufficient; and further, that the greater solidity of structure makes replacement on a large scale physically and chemically difficult. For, on the one hand, we see even in lower animals that aquatic animals, on account of containing a greater quantity of moisture, possess a greater recuperative power than land animals of