Swallows, in hawking through the air for insects, do not snap their game up as do the true flycatchers. Their mouths are little nets which they drive through the air with the speed of airplanes. A few mornings ago the air was cold, but it contained many gauzy, fuzzy insects from the size of mosquitoes down to gnats. They kept near the ground. I happened to be sitting on the sunny side of a rock and saw the swallows sweep past. One came by within ten feet of me and drove straight on to a very conspicuous insect which disappeared in his open mouth in a flash. How many hundreds or thousands of such insects they must devour each day! Then think of how many insects the flycatchers and warblers and other insect-eating birds must consume in the course of a season! IV We little suspect how the woods and wayside places swarm with life. We see little of it unless we watch and wait. The wild creatures are cautious about revealing themselves: their enemies are on the lookout for them. Certain woods at night are alive with flying squirrels which, except for some accident, we never see by day. Then there are the night prowlers--skunks, foxes, coons, minks, and owls--yes, and mice. 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.