The wild mice we rarely see. The little shrew mole, which I know is active at night, I have never seen but once. I once set a trap, called the delusion trap, in the woods by some rocks where I had no reason to suspect there were more mice than elsewhere, and two mornings later it was literally packed full of mice, half a dozen or more.
Turn over a stone in the fields and behold the consternation among the small folk beneath it,—ants, slugs, bugs, worms, spiders,—all objecting to the full light of day, not because their deeds are evil, but because the instinct of self-preservation prompts this course. As I write these sentences, a chipmunk, who has his den in the bank by the roadside near by, is very busy storing up some half-ripe currants which grew on a bush a few yards away. Of course the currants will ferment and rot, but that consideration does not disturb him; the seeds will keep, and they are what he is after. In the early summer, before any of the nuts and grains are ripened, the high cost of living among the lesser rodents is very great, and they resort to all sorts of makeshifts.
V
In regard to this fullness of life in the hidden places of nature, Darwin says as much of the world as a whole:
Well may we affirm that every part of the world is inhabitable. Whether lakes of brine or those subterranean ones hidden beneath volcanic mountains—warm mineral springs—the wide expanse and depth of the ocean, the upper regions of the atmosphere, and even the surface of perpetual snow—all support organic beings.
Never before was there such a lover of natural history as Darwin. In the earth, in the air, in the water, in the rocks, in the sand, in the mud—he scanned the great biological record of the globe as it was never scanned before. During the voyage of the Beagle he shirked no hardships to add to his stores of natural knowledge. He would leave the comfortable ship while it was making its surveys, and make journeys of hundreds of miles on horseback through rough and dangerous regions to glean new facts. Grass and water for his mules, and geology or botany or zoölogy or anthropology for himself, and he was happy. At a great altitude in the Andes the people had shortness of breath which they called "puna," and they ate onions to correct it. Darwin says, with a twinkle in his eye, "For my part I found nothing so good as the fossil shells."
His Beagle voyage is a regular magazine of natural-history knowledge. Was any country ever before so searched and sifted for its biological facts? In lakes and rivers, in swamps, in woods, everywhere his insatiable eye penetrated. One re-reads him always with a different purpose in view. If you happen to be interested in insects, you read him for that; if in birds, you read him for that; if in mammals, in fossils, in reptiles, in volcanoes, in anthropology, you read him with each of these subjects in mind. I recently had in mind the problem of the soaring condor, and I re-read him for that, and, sure enough, he had studied and mastered that subject, too. If you are interested in seeing how the biological characteristics of the two continents, North and South America, agree or contrast with each other, you will find what you wish to know. You will learn that in South America the lightning-bugs and glowworms of many kinds are the same as in North America; that the beetle, or elator, when placed upon its back, snaps itself up in the air and falls upon its feet, as our species does; that the obscene fungus, or Phallus, taints the tropical forests, as a similar species at times taints our dooryards and pasture-borders; and that the mud-dauber wasps stuff their clay cells with half-dead spiders for their young, just as in North America. Of course there are new species of animal and plant life, but not many. The influence of environment in modifying species is constantly in his mind.
VI
The naturalist can content himself with a day of little things. If he can read only a word of one syllable in the book of nature, he will make the most of that. I read such a word the other morning when I perceived, when watching a young but fully fledged junco, or snowbird, that its markings Were like those of the vesper sparrow. The young of birds always for a brief period repeat the markings of the birds of the parent stem from which they are an offshoot. Thus, the young of our robins have speckled breasts, betraying their thrush kinship. And the young junco shows, in its striped appearance of breast and back, and the lateral white quills in the tail, its kinship to the grass finch or vesper sparrow. The slate-color soon obliterates most of these signs, but the white quills remain. It has departed from the nesting-habits of its forbears. The vesper sparrow nests upon the ground in the open fields, but the junco chooses a mossy bank or tussock by the roadside, or in the woods, and constructs a very artistic nest of dry grass and hair which is so well hidden that the passer-by seldom detects it.
Another small word I read about certain of the rocks in my native Catskills, a laminated, blue-gray sandstone, that when you have split them open with steel wedges and a big hammer, or blown them up with dynamite, instead of the gray fresh surface of the rock greeting you, it is often a surface of red mud, as if the surface had been enameled or electrotyped with mud. It appears to date from the first muddy day of creation. I have such a one for my doorstone at Woodchuck Lodge. It is amusing to see the sweepers and scrubbers of doorstones fall upon it with soap and hot water, and utterly fail to make any impression upon it. Nowhere else have I seen rocks casehardened with primal mud. The fresh-water origin of the Catskill rocks no doubt in some way accounts for it.