In fact, the growth of the nucleus of the spermatozoid has given to its substance the same power of development as to that of the nucleus of the egg. Both enter into conjugation in equal parts, which symbolizes the social equality and the rights of the two sexes!
The signification of these facts is as follows: as soon as, in the course of development, the conjugated nuclei divide again into two cells, as in Figs. 7 to 10, of Plate I, each of these two cells contains almost the same quantity of paternal as maternal chromatin. We do not say exactly as much, for the paternal and maternal influences are not divided equally in the descendants. This phenomenon may be explained by what Semon calls alternating ecphoria in mnemic dichotomy. (Vide infra.) As cell division continues in the same way during embryonic life, it follows that each cell, or at least each nucleus of the future organism, will contain on the average half its substance and energy from the paternal and half from the maternal side.
Heredity. The Mneme.—The secret of heredity lies in the phenomena which have been just described. Hereditary influence preserves all its primary power and original qualities in the chromosomes, which enlarge and divide, while the vitelline substance, absorbed by the chromosomes and transformed by the vital chemical processes into the specific substance of the chromosomes, loses its specific and plastic vital energy, as completely as the food which we swallow loses its energy in forming the structure of our living organs. We do not acquire any of the characters of the ox by eating beefsteaks; and the spermatozoid, after eating much vitelline protoplasm, preserves its own hereditary energies, increased and fortified, but without change in their qualities.
In this way the nuclear chromatin of our germinal cells becomes the carrier of all the hereditary qualities of the species (hereditary mneme), and more especially those of our direct ancestors. The uniformity of the intracellular phenomena in cell division and conjugation proves, however, that, without being capable of reproducing the individual, the other non-germinal cells of the body may also possess these hereditary energies, and that there exists, hidden behind all these facts, an unknown law of life, the explanation of which is reserved for the future.
However, a recent work based on an idea of the physiologist, E. Hering, which looks upon instinct as a kind of memory of the species, opens up a new horizon. I refer to the book of Richard Semon: "The mneme considered as the conservative principle in the transmutations of organic life." (Die Mneme als erhaltendes Prinzip im Wechsel des organischen Geschehens, Leipzig, 1904.)
Conception of Irritation.[1]—By the aid of the fundamental facts of morphological science, biological and psychological, Semon proves that Hering's idea is more than an analogy, and that there is a fundamental identity in the mechanism of organic life. In order to avoid the terminology of psychology which tends to be equivocal, Semon employs some new terms to designate his new ideas, based on the fundamental conception of irritation in its physiological sense.
Semon defines irritation as an energetic action on the organism which determines a series of complicated changes in the irritable substance of the living organism. The condition of the organism thus modified, which lasts as long as the irritation, is called by Semon the state of irritation. Before the action of irritation, the organism is in a condition which Semon calls the primary state of indifference, and after its action, in the secondary state of indifference.
Engram. Ecphoria.—If, when an irritation has entirely ceased, the irritable substance of the living organism becomes modified permanently during its secondary state of indifference, Semon calls the action engraphic. To the modification itself he gives the word engram. The sum of the hereditary and individual engrams thus produced in a living organism is designated by the term mneme. Semon gives the name ecphoria to the revival of the engram by the repetition of part only of the original irritation, or by the entire but weakened reproduction of the whole state of irritation of the organism, which was originally produced in a synchronous manner with the primary irritation.
Thus, an engram may be ecphoriated (that is to say, reproduced or revived) by the return of one part of the complex of primary irritations which produced it. A young dog, for example, is attacked by urchins who throw stones at it. It experiences two kinds of irritation: (1) the urchins stooping down and throwing stones (optic irritation); (2) the pain caused by the stones (tactile irritation).
In its brain are produced two associated series of corresponding engrams. Previously, this dog did not react when it saw people stoop down. From this moment it will run away and howl at the sight, without any stone being thrown at it. Thus the tactile engram will be ecphoriated by the repetition of the original associated irritation. In the same way, the image of a tree in a known landscape will ecphoriate the entire landscape.