. An examination of Weismannism [microform]. Heredity; Evolution; Hérédité; Evolution. Later Additions up to the year 1892. 43 the offspring of the same parents do not all precisely resemble one another. These, be it observed, are the only two functions which Weismann's theory of polar bodies subserves in relation to his theory of germ-plasm. But, it appears to me, neither of these functions is necessary, in so far as any requirements of the latter theory are concerned. For surely, polar bodies or no polar bodies, there is already a mechanism at work in each ontogeny which is of itself suffici
. An examination of Weismannism [microform]. Heredity; Evolution; Hérédité; Evolution. Later Additions up to the year 1892. 43 the offspring of the same parents do not all precisely resemble one another. These, be it observed, are the only two functions which Weismann's theory of polar bodies subserves in relation to his theory of germ-plasm. But, it appears to me, neither of these functions is necessary, in so far as any requirements of the latter theory are concerned. For surely, polar bodies or no polar bodies, there is already a mechanism at work in each ontogeny which is of itself sufficient to discharge both these functions, and so to anticipate both the supposed difficulties which the subsidiary theory is adduced to meet. The very essence of ontogeny, as a process, itself consists in a continuous succession of nuclear divisions—and this not only as regards sovnatic-cells, but also as regards germ-cells. Now, in the great majority of organisms, there is an infinitely greater number of germ cells (both male and female) than can possibly be required either for the purpose of getting rid of any excess of germ-plasms in the nucleus ol each cell, or of preventing the germ-plasms of any one germ-cell precisely resembling those of any other. If every plant or animal produced only a single female-cell or a single male-cell, then indeed we might require from Professor Weismann a demon- .stration of some special mechanism to secure the ex- pulsion of half its ancestral germ-plasms ; since other- wise the single female-cell or male-cell would have to increase its dimensions in each successive generation. But, as matters actually stand, nature seems to have made much more than ample provision for prevent- ing the undue accumulation of ancestral germ-plasms in any individual germ-cell, by enormously multiply- ing, through continuous division and subdivision, the. % !. Please note that these images are extracted from scanned page images that may have been digitally enh
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