Page:The Effect of External Influences upon Development.djvu/34

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30
The Romanes Lecture 1894

but is merely the stimulus which not only results in the formation of rudimentary ovaries, but at the same time calls forth all the other distinctive characters of the workers. It appears to me to be doubly incorrect to look upon the poor nourishment as the actual cause; for such a view not only confuses the stimulus with the real cause, but also fails to distinguish between an organ that becomes rudimentary and one that is simply imperfectly developed. Moreover the fact is overlooked that the ovaries of the workers are actually rudimentary organs: a great proportion of their really essential parts have disappeared, while only a small remnant is retained. The ovary of the queen-bee consists of from 180 to 200 egg-tubes, and numerous eggs may become mature in one of these. The queen is accordingly able in the course of her life to produce an immense number of eggs,—more than a hundred thousand. The ovary of the worker on the other hand contains from two to six egg-tubes only, and no matter how rich the food may be, no more can be formed in the imaginal state. The workers certainly produce eggs occasionally, when they have received exceptionally rich nourishment in the imaginal-stage; but even then their fertility is never great, for only a few eggs can find room to ripen at a time in the small number of ovarian-tubes present. And this is only exceptional, for the workers ordinarily only take just enough food to serve for the sustenance of the body, and not sufficient to allow the small egg-germs in their ovarian-tubes to become ripe.

It is now possible to show by experiment that poor