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Updated: June 18, 2025
It is like a self-perpetuating, close corporation; and the somatoplasm has no means of either controlling it or of gaining representation in it. If it be well nourished, the germ-cells will have abundant nutriment; and, conversely, if it be weak and sickly, the germ-cells will be arrested in their growth.
The massacre or expulsion of the drones would have to impress itself on the germ-cells of an onlooking queen, and the imprisonment of the queen on the sperm-cells of the drones and in such a way, moreover, as to be afterwards developed into action in the neuters only.
It is, however, possible that the mere injury introduced and encouraged the growth of certain microbes, which, spreading through the organism, sometimes reached the germ-cells, and thus transmitted a diseased condition to the offspring."
"Leaving on one side, for the moment, these doubtful and insufficiently investigated cases, we may still maintain that the assumption that changes induced by external conditions in the organism as a whole are communicated to the germ-cells after the manner indicated in Darwin's hypothesis of pangenesis, is wholly unnecessary for the explanation of these phenomena.
Now the stimulus which had excited this variation must have been applied early in embryonic life, or perhaps during the formation or maturing of the germ-cells themselves. Such a variation we call a congenital variation.
The germ-cells are thus the bearers of heredity because they contain samples, so to speak, of all the organs of the body. In heredity, according to Weismann's theory, the egg is the centre of control, the continuous germ-plasm the source of all transmitted changes; according to Darwin's theory, the body is the source, and the egg is derived in great part at least from it.
Professor Weismann's theory is, that at every new birth a part of the substance which proceeds from parents and which goes to form the new embryo is not used up in forming the new animal, but remains apart to generate the germ-cells or perhaps I should say "germ-plasm" which the new animal itself will in due course issue.
How far this can be shown to be probable is, of course, another matter, but I am not immediately concerned with this; all I am concerned with now is to show that the germ-cells not unfrequently become permanently affected by events that have made a profound impression upon the somatic cells, in so far that they transmit an obvious reminiscence of the impression to the embryos which they go subsequently towards forming.
Mendelian phenomena of inheritance, confirmed and extended by numerous workers with plants and animals, prove that in many cases portions of the streams of germ plasm that combine to form the hereditary content of organisms may retain their individuality during embryonic and later development, and that they may emerge in their original purity when the germ-cells destined to form a later generation undergo the preparatory processes of maturation.
The sum total of all these engrams, in a living human being, according to the theory advanced, is given the name of mnema. That which the child receives in the way of energies contained in the germ-cells from its ancestors is his hereditary mnema. And that which he acquires in the course of his own individual life is his acquired or individual mnema.
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