One day in January, weary of my futile search, it occurs to me to strip off, in shreds, a lichen, the Wall Parmelia, which here and there carpets thinly with its yellow rosettes the base and the thicker branches of my terebinth. I examine my harvest through the lens, in my study. What is this? A magnificent discovery! In my scrap of lichen, no larger than a finger-nail, I discover a world. On the inner surface, in the winding crevices between the scales, are encrusted vast numbers of tiny red bodies barely a millimetre [64] in length. Some of them are entire and oval in shape; some, truncated and empty, display open pouches with pointed ends. All are plainly segmented. Can it be that I have before my eyes the Louse’s eggs, of which some are old and empty, while others are recent and contain their germ? This idea is soon disposed of: an egg has not this segmentation like that of an insect’s abdomen. Here is a more significant fact: a head and antennæ are visible in front, while legs may be seen underneath; the whole is dry and brittle. These specks, accordingly, once lived and walked. Are they dead now? No, for when I crush them with the point of a needle traces of moisture gush forth, a sign of a living organism. Only the shell is dead. The tiny creature, capable at first of movement, endowed with legs and antennæ, wandered for some time under cover of the lichen; then, before it became inert, it settled down on a suitable spot. There it turned its shrivelled skin, now an amber-coloured pellicle, into a mummy’s sarcophagus in which the organism makes ready for a new life. When the time comes, we shall discover the origin of this curious object, which was an animal and now deserves the name of egg. What my own familiar terebinth has shown me in the enclosure, I ought to see repeated in the open country. Sure enough, I do see it; but this time it is not under lichens, for the bark of the tree is most often bare. There is no lack of other shelter. Some twigs of terebinth have been cut by the clumsy bill-hooks of the brushwood-gleaners, leaving a ragged section. The wood is split into deep fissures; the loose bark comes away in tatters. Once dry, these ruins are a mine of wealth. In the narrowest crevices, in the cracks of the wood and under the splintered bark, there are great numbers of the atoms that interest me so greatly. To judge by their colour there are at least two kinds. Some are red; the others are black. These latter were scarce under the lichens on my terebinth; here they predominate largely. I collect some of both kinds. And now we must have patience. I have hopes that the answer to the riddle will be found.