ABSTRACT
The case of natural selection is quite similar, for it also employs merely these two organic constructive forces, the physiological functions of Adaptation and Heredity, in order to produce the different species. Accordingly as Inheritance or Adaptation predominates in the struggle, the specific form either remains constant or changes into a new species. There is a constant fluctuation from year to year occasioned by one or other series of animals and plants predominating, and that every year the struggle for life somewhat alters their relations. Thus the prosperity, nay, even the existence of whole populations can be indirectly determined by a single small animal or vegetable form in itself extremely insignificant. Hence the selection of cells, which according to Roux takes place everywhere in the tissues, might be termed Cellular Selection, in opposition to the Personal Selection which Darwin first pointed out between independent individuals.
