The first, then, and most important element of heredity is that there should be unbroken continuity, and hence sameness of personality, between parents and offspring, in neither more nor less than the same sense as that in which any other two personalities are said to be the same.  The repetition, therefore, of its developmental stages by any offspring must be regarded as something which the embryo repeating them has already done once, in the person of one or other parent; and if once, then, as many times as there have been generations between any given embryo now repeating it, and the point in life from which we started—­say, for example, the amoeba.  In the case of asexually and sexually produced organisms alike, the offspring must be held to continue the personality of the parent or parents, and hence on the occasion of every fresh development, to be repeating something which in the person of its parent or parents it has done once, and if once, then any number of times, already.

It is obvious, therefore, that the germ-plasm (or whatever the fancy word for it may be) of any one generation is as physically identical with the germ-plasm of its predecessor as any two things can be.  The difference between Professor Weismann and, we will say, Heringians consists in the fact that the first maintains the new germ-plasm when on the point of repeating its developmental processes to take practically no cognisance of anything that has happened to it since the last occasion on which it developed itself; while the latter maintain that offspring takes much the same kind of account of what has happened to it in the persons of its parents since the last occasion on which it developed itself, as people in ordinary life take things that happen to them.  In daily life people let fairly normal circumstances come and go without much heed as matters of course.  If they have been lucky they make a note of it and try to repeat their success.  If they have been unfortunate but have recovered rapidly they soon forget it; if they have suffered long and deeply they grizzle over it and are scared and scarred by it for a long time.  The question is one of cognisance or non-cognisance on the part of the new germs, of the more profound impressions made on them while they were one with their parents, between the occasion of their last preceding development and the new course on which they are about to enter.  Those who accept the theory put forward independently by Professor Hering of Prague (whose work on this subject is translated in my book Unconscious Memory) and by myself in Life and Habit, believe in cognisance as do Lamarckians generally.  Weismannites, and with them the orthodoxy of English science, find non-cognisance more acceptable.