The laws of heredity : their definite meaning and interpretation / editor: Henry Smith Williams, M.D., LL.D.
- Date:
- [1914]
Licence: Public Domain Mark
Credit: The laws of heredity : their definite meaning and interpretation / editor: Henry Smith Williams, M.D., LL.D. Source: Wellcome Collection.
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![higher organism become differentiated into di- vergent groups, capable of performing different functions. And, from our present standpoint, the thing to be particularly noted is that the tissue serving the purpose of reproduction of the species is segregated; and that this segregation takes place, in the case of higher animals, at a very early stage of the embryonic development of the individual. The Continuity of the Germ-Plasm The full significance, from the standpoint of heredity, of this segregation of the germ-plasm has been appreciated only within comparatively re- cent years. It was not until Professor August Weismann made special studies in this field, about thirty years ago, that the subject prominently at- tracted the attention of biologists. Weismann had been struck by the fact that single-celled organisms, owing to the character of their reproduction by division, are, as he phrased it, “potentially immortal.” They do not normally die, but rejuvenate themselves by division, a given individual becoming two, and these two presently becoming four, and so on in an unending geomet- rical progression, in which the descendants of any generation whatever might be regarded as repre- senting the divided substance and personality of the original ancestor. Weismann made application of this thought [3]](https://iiif.wellcomecollection.org/image/b33628415_0005.jp2/full/800%2C/0/default.jpg)
