merdam's time. His investigations placed future enquirers on a vantage ground which they could not otherwise have attained, and, had it not been for the discoveries of Swammerdam, we might have wanted many of those made by Reaumur, Huber, and others.
So early as the year 1667 he had prepared and partly printed a treatise on the Ephemerus or Day-fly, as he calls it, but it was not published till 1675. It first appeared in Dutch under the title of Ephemeri vita. He states that his principal object in laying it before the public was to give us wretched mortals a lively image of the shortness of human life, and thereby induce us, by frequent admonitions, to aspire to a better state of being. It accordingly abounds with pious reflections and meditations to such a degree that the subject by which they are suggested is, in some instances, almost lost sight of. In most of the translations which have appeared these portions are omitted, as well as the numerous Dutch sentences in prose and verse which he has liberally introduced. He traces with great care and assiduity the whole changes of the insect from the egg to the perfect state, in which it lives only four or five hours. The internal anatomy is also elaborately described and figured, constituting by far the most valuable portion of the work. The following remarks occur towards the close:—"All of these insects die in the very short space of time just mentioned, nor do any of them,—which is a matter very worthy of observation,—die a natural death on land; all of them invariably go to the water again, after they have