Problems of biology / [George Sandeman].

  • Sandeman, George
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: Problems of biology / [George Sandeman]. Source: Wellcome Collection.

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    “ The comparison of different organisms suffers not only from our want of knowledge, but also from the absence, due to dissimilarity of organisation, of a common measure which should assign the value and therewith the true difference (of qualities). Thus we are unable to compare the fungus, the fern, the pine, and the fruit tree otherwise than by pointing out that in one of these plants there is a quality (A/erkma/J which does not occur in another, and that in one case it has this nature (Beschaffe7iheit) and in the other case that other nature. But the difference can in no case be expressed as quantity, and thus as plainly presentable magnitude. Therefore all systematic distinction and estima- tion is more or less arbitrary, and all inference from them, for the purposes of phylogenetic theory, is hypothetical. “There is, however, a condition in which the qualities which cannot be exactly compared and estimated are elim- inated, and in which all organisms are reduced to a similar form and structure. It is the first and unicellular stage of development, for in the ovum all animals and plants are similar. But the ovum contains all essential (wesentlich) qualities just as much as the developed organism, and or- ganisms differ from one another not less as ova than they do in the developed condition. The species is as completely contained in the hen’s egg as in the hen, and the hen’s egg is as different from the frog’s egg as is the hen from the frog. If it seems otherwise to us it is only because many- distinguishing qualities may be seized in the hen and the frog, while the distinguishing qualities in the ovum are hidden from us. “ The states of the ova are the short beginnings of the individual histories of development, and as such may be compared, as it were, with short segments of different curves. The short segments appear to be all similar and to be all straight, although in them the essence and the mathematical formula of the different curves is as sharply expressed as when they have been lengthened so as to show
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