pared the specimens he obtained with the accounts of the best authors, and afterwards arranged them in certain classes. When more advanced in years he applied himself most diligently to anatomy and medicine, all the while having his mind bent on the attainment of some important objects. He often spent both day and night in searching for and examining such insects as he could find, not only in his native district, but also in other parts of Holland. With this view he ransacked the air, the land, and the water; fields, meadows, pastures, corn-lands, downs, wastes, sand-hills; rivers, ponds, wells, lakes, seas, and their shores and banks; trees, plants, ruins, caves, uninhabited places, and even bog-houses, in order that he might make himself acquainted with the nests of insects, their food, manner of living, diseases, metamorphoses, and modes of propagation. And it may be affirmed, that in these particulars he discovered more facts and valuable information, even in his early youth, than all the known authors of preceding ages. However incredible this may appear, it is a fact that cannot be questioned, for the most competent judges have borne testimony to its truth."
He prosecuted his medical studies for a length of time in his native city, but afterwards repaired to Leyden, to avail himself of the advantages of its celebrated university. The surgical department was then under the direction of John Van Horne, and Francis Silvius de la Boe was professor of medicine, both of whom were men of celebrity.
