The science & philosophy of the organism / by Hans Driesch.

  • Driesch, Hans, 1867-1941.
Date:
1929
Catalogue details

Licence: In copyright

Credit: The science & philosophy of the organism / by Hans Driesch. Source: Wellcome Collection.

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    are actually visible as parts of the last one. The great em- bryologist, Carl Ernst von Baer, most clearly appreciated these analytical differences between animal and vegetable morpho- genesis. They become a little less marked if we remember that plants, in a certain respect, are not simple individuals but colonies, and that among the corals, hydroids, bryozoa, and ascidia we find analogies to plants in the animal kingdom ; but nevertheless, the differences we have stated are not extinguished by such reasoning. It seems almost wholly due to the occurrence of so many foldings and bendings and migrations of cells and complexes of cells in animal morpho- genesis that an earlier stage of their development seems lost in the later one ; those processes are almost entirely wanting in plants, even if we study their very first ontogenetic stages. If we say that almost all production of surfaces goes on outside in plants, inside in animals, we shall have adequately described the difference. And this feature again leads to the further diversity between animals and plants which is best expressed by calling the former “ closed ”, the latter “ open ” forms : animals reach a point where they are finished, plants never are finished, at least in most cases. We have already said that the embryological process appears under the form of a production of visible manifoldness, and it will be important for what is to follow to analyse the concept of manifoldness a little more in detail. We call manifold everything that is not elemental, but is a combination of parts. And in the first place, we may speak of a numerical manifoldness, that is, one which only refers to the number of elements in question. In this respect, the atom of iron is more manifold than the atom of hydrogen ; for there are more electrons in the former. But there may be a different manifoldness of construction in the realm of the same numerical manifoldness. A com- munity of points which represents a flower has a higher degree of this sort of manifoldness than has the same com- munity of points if arranged in squares, the relations between the points being more manifold in the first case than in the second.