One of Herbert Spencer's questions was, Why do animals and birds of prey have their eyes in front, and others, as sheep and domestic fowl, on the side of the head? Man, then, by the position of his eyes belongs to the predaceous animals. I have never been greatly interested in spiders, but I have always wanted to know how a certain spider managed to stretch her cable squarely across the road in the woods about my height from the ground? Why are mud turtles so wild? Why is the excrement of the young of some birds carried away by the parents, while with others it is voided from the nest? Among certain of our birds the family relation, more or less marked, is kept up a long time after the young have left the nest. One sees the parent birds and the young going about in loose flocks often till late into the fall. Of what birds is this true?
The questions I have suggested are not important; they do not hold the key to any great storehouse of natural knowledge. Their only value is as a means to quicken the powers of observation. We see vaguely, diffusely. Concentrate the attention--not to the extent of missing total effects, as the specialist so often does, but for the purpose of reading correctly the play of life that is constantly going about us.
Nature's book is like any other book: you must open the covers; you must fix your eyes upon the text; you must get into the spirit of it. When you have read one sentence correctly you are so much the better prepared to read the next one.
A world of nature about us that we are quite apt to be oblivious to, except as it results in our annoyance, is the insect world. We do not take an intelligent interest in the ants, or the bees, or the moths, or the butterflies, yet here is a field of observation that will amply repay one. One day in a great city I saw a butterfly calmly winging its way high above the crowded street. I knew it was the monarch (_Anosia plexippus_), probably the greatest traveler of all our butterflies. It is quite certain that they migrate to the South in the fall, and that many return in the spring. I learn from Mr. Holland's Butterfly Book in this library that they have even crossed both oceans--of course, by catching a ride on vessels--and are now found in Australia and in the Philippines, and they have been collected in England. Have you not seen its chrysalis suspended from some weed or bush, looking like the trunk from some tiny warrior encased in pale-green armor, riveted with gold-headed rivets, a broad, heavy shield over the abdomen, and plate upon plate over the shoulders and back? It is a milkweed butterfly, and will serve as a good introduction to this new world of winged life. Early last spring I found upon the window of my cabin in the woods a butterfly that had evidently hybernated in some snug crack or corner of the building. This was the mourning cloak, with me the first vernal butterfly. When one sees this butterfly dancing through the open sunny woods in March or early April he may know spring has really come and that the first hepatica will soon open its blue eye.