History makes a strong appeal to many people, and those who are fascinated thereby will find endless amusement in reading old books on the microscope and its objects. In the preface to Mouffet’s _Insectorum Theatrum_, one of the earliest books on insects, we read the following quaint lines: “If you will take lenticular object glasses of Crystal (for though you have Lynx his eyes, they are necessary in searching for atoms) you will admire to see the Fleas that are curasheers, and their hollow trunk to torture men, which is a bitter plague to maids, you shall see the eyes of Lice sticking forth, and their horns, their bodies crammed all over, their whole substance diaphanous, and through that, the motion of their heart and blood. Also little Handworms, which are indivisible, they are so small, being with a needle prickt forth from their trenches near the pool of water which they have made in the skin, and being laid upon one’s nail, will discover by the sunlight their red heads and feet they creep withal.” The creatures called Handworms are itch mites, which tunnel in the human skin. In our chapter on Nature Study and the Microscope we refer to the brown patches to be found on the backs of fern fronds; it is interesting to note that so long ago as 1646 Sir Thomas Browne had quite a good idea of their structure. Describing them, he said: “Whether these little dusty particles, upon the lower side of the leaves be seeds we have not yet been able to determine by any germination. But, by the help of magnifying glasses we find these dusty atoms to be round at first and fully representing seeds out of which at last proceed little mites, almost invisible, so that such as are old stand open, as being emptied of some bodies firstly included, which though discernible in Hartstongue, is more notoriously discoverable, in some differences, of Brake or Fern.” Two years earlier a noted scientist, Hodierna, had made a special study of the eyes of insects and, considering the crude instruments with which he must have worked, his descriptions are wonderfully accurate. Of the house fly he wrote: “The head is all eyes, prominent and without lids, lashes or brows. It is plumed with hairs like that of an ostrich and has two little pear shaped bodies hanging from the middle of the forehead. The proboscis which arises from the snout can be extended freely and stretched forth to suck up humours and can afterwards be directed back through the mouth and taken into the gullet. This instinct nature has given the creature according to its need, for it is without a neck and cannot stretch forth its head to obtain its food, as is also the case with the elephant.” The author’s knowledge of the house fly was evidently greater than his knowledge of the ostrich, for the bird has anything but a plumed head. The eye of the insect he compares to a white mulberry.