We approach the problem of heredity from a new direction and with new eyes. Let us picture to ourselves (as has been suggested), instead of a succession of lives, a single life which goes on like the continuous germ-plasm of some biologists, and never grows old or dies. This one continuous life would pass through every stage of the succession of lives from the jelly-speck onwards. One immortal developing creature would accomplish (in our picture) the whole evolution from the original protoplasm to man. And this development would be effected by forming habits and rising step by step in and through and upon them. Is this in fact what actually has been done along the path of the ascent of species? That is the question which at once springs to our lips. Is heredity akin to the habit-memory which is preserved in our brains and bodies? There are men who tell us that the best conception of heredity they can form is something of this kind. They tell us that they think of individual lives as inscribing on germ-cells, by constant repetition, effects of what they have done. They tell us that the habit-memory of ancestral and thus communicated experience enables the baby to pump food into its mouth with that accurate adjustment of muscular means to exterior conditions and the principles of hydrostatics which it always shows. They go even farther and tell us that the development of any embryo from any egg is on the same lines of unfolding the habit-memories essential to its living as it does. Life in progressing from the single cell learnt, they think, by degrees, and consolidated its lessons into motor-habits graven in living stuff. Sometimes they point to the nucleus of the germ-cell as possibly the instrument for preserving these habits for other members of the race as the brain preserves less established habits for the man; sometimes they say that the cytoplasm acts in the same way. And whether we accept these suggestions or reject them we may recognize with some satisfaction that throughout the whole plan there runs the belief (or assumption—what you will) that function is primary, not structure, though structure once organized is the instrument and condition that contributes to the shaping of specific character.
Again we find ourselves both ready and called upon to emphasize the reality and the conservative office of matter, yet to regard it as subordinate to the reality and the initiative of life. We acknowledge once more the immeasurable import for life of its relations with matter. When structure is organized for function, when habit-memories become instrumental for life, function and life are in turn shaped by their instrument. Hence, probably, we have that condensed and fragmentary representation by the developing embryo of stages through which life passed slowly in epochs long ago, and during which (according to this hypothesis) it registered the fruits of its effort, by repetition after repetition, in the cell. The embryo chicken, the embryo child, both show in the course of their development signs (for instance the gill-clefts of the fish) of stages through which life had to pass before it became chicken or child life. But they pass very quickly from sign to sign. 'It took thousands of years to produce the first chicken, but the hen's egg reaches the same level in three weeks.' Each is obliged to pass these stages, it seems; the 'organ-forming substances' (as some say) of the germ-cell compel it, or (shall we carry our thought farther and say) the habit-memories recorded in it must be worked out lest the creature be brought to confusion; as the habit-memories of a pianist are and must be when he gives aright his rendering of the music he had learnt.
The memory-hypothesis concerning heredity does not involve the idea of compulsion or doom, it leaves room for the creature to work out its 'own salvation' on a basis inheritance supplies. It does not of itself regard the creature as doomed; whether the child or the chick is or is not doomed depends on what it is, that is to say, upon the character not upon the mode of its inheritance. Chick-character is one of doom; not so child-character. The child, starting from the point his race has reached as a race, may go on in virtue of an endowment of impulsive and creative power and a flexible brain and body absent in the chick. He may build his house of life, adorning or disfiguring his inheritance with a new-made character that is his own. This fruitful and interesting hypothesis of memory-inheritance may or may not stand tests that are to come. But we may accept it provisionally as what it is, sure that if it is displaced its successor will be more welcome still. That is the way of science; we pass always from good to better, from a guess that holds for one range of facts to another that holds for more.
CHAPTER VII
And is this life but the child of death? Then
blessed also be the word Death, the mother of life;
I will no more call thee Marah, but Naomi; for thou
art not bitter, but sweet; more pleasant, though
swifter in thy gait, than roe or hind.