The reader has doubtless often seen those little picture-puzzles, variously labelled “Where's the Cat?” or “Mad Bull,” or “Burglar,” or “Policeman,” or “Snake in the Grass,” etc., in which the thing named and to be discovered is formed by branches and foliage and by running water and drapery and lights and shadows in the sketch. At first one finds it extremely difficult to detect this picture within a picture; and at last, with the suddenness with which one invariably detects a dull-coloured snake, seen previously but not distinguished—the object sought for appears, and is thereafter so plain to the eye that one cannot look at the sketch, even held at a distance, without seeing the cat or policeman, or whatever it happens to be. And after patiently studying some scores or hundreds of these puzzles one gets to know just how to find the thing concealed, and finds it quickly—almost at a glance at last. Now, the ingenious person that first invented this pretty puzzle probably had no thought of Nature, with her curious imitative and protective resemblances, in his mind; yet he might very well have taken the hint from Nature, for this is what she does. The animal that must be seen to be avoided, and the animal that must be seen to be taken, are there in her picture, sketched in with such cunning art that to the uninstructed eye they form only portions of branch and foliage and shadow and sunlight above, and dull-hued or variegated earth and stones and dead and withering herbage underneath.
It is possible that slight differences may exist in the seeing powers of different nations, due to the effect of physical conditions: thus, the inhabitants of mountainous districts and of dry elevated tablelands may have a better sight than dwellers in low, humid and level regions, although just the reverse may be the case. Among European nations the Germans are generally supposed to have weak eyes, owing, some imagine, to their excessive indulgence in tobacco, while others attribute the supposed decay to the form of type used in their books, which requires closer looking at than ours in reading. That they will deteriorate still further in this direction, and from being a spectacled people become a blind one, to the joy of their enemies, is not likely to happen, and probably the decadence has been a great deal exaggerated. Animals living in darkness become near-sighted, and then nearer-sighted still and so on progressively until the vanishing point is reached. In a community or nation a similar decline might begin from much reading of German books, or perpetual smoking of pipes with big china bowls, or from some other unknown cause; but the decay could not progress far, because there is nothing in man to take the place of sight, as there is in the blind cave rats and fishes and insects. And if we could survey mankind from China to Peru with all the scientific appliances which are brought to bear on the Board-school children in London and on the nation generally, the differences in the powers of vision in the various races, nations and tribes would probably appear very insignificant. The mistake which eye specialists and writers on the eye make is that they think too much about the eye. When they affirm that the conditions of our civilization are highly injurious to the sight, do they mean all the million conditions or sets of conditions embraced by our system, with the infinite variety of occupations and modes of living which men have, from the lighthouse-keeper to the worker underground, whose day is the dim glimmer of a miner's lamp? “An organ exercised beyond its wont will grow and thus meet increase of demand by increase of supply,” Herbert Spencer says; but, he adds, there is a limit soon reached, beyond which it is impossible to go. This increase of demand with us is everywhere—now on this organ and now on that, according to our work and way of life, and the eye is in no worse case than the other organs. There are among us many cases of heart complaint; civilization, in such cases, has put too great a strain on that organ, and it has reached the limit beyond which it cannot go. And so with the eye. The total number of the defective among us is no doubt very large, for we know that our system of life retards—it cannot effectually prevent—the healthy action of natural selection. Nature pulls one way and we pull the other, compassionately trying to save the unfit from the consequences of their unfitness. The humane instinct compels us; but the cruel instinct of the savage, who hates the sick and the unfit as the inferior animals do, is less painful to contemplate than that mistaken or perverted compassion which seeks to perpetuate unfitness, and in the interest of suffering individuals inflicts a lasting injury on the race.
Pelleschi, in his admirable book on the Chaco Indians, says that malformations are never seen in these savages, that physically they are all perfect men; and he remarks that in their exceedingly hard struggle for existence in a thorny wilderness, beset with perils, any bodily defect or ailment would be fatal. And as the eye in their life is the most important organ, it must be an eye without flaw. In this circumstance only do savages differ from us—namely, in the absence or rarity of defective eyes among them; and when those who, like Mr. Brudenell Carter, believe in the decadence of the eye in civilized man quote Humboldt's words about the miraculous sight of South American savages, they quote an error. It is not strange that Humboldt should have fallen into it, for, after all, he had only the means which we all possess of finding out things—a limited sight and a fallible mind. Like the savage, he had trained his faculties to observe and infer, and his inferences like those of the savages, were sometimes wrong.
The savage sight is no better than ours for the simple reason that a better is not required. Nature has given to him, as to all her creatures, only what was necessary and nothing for ostentation. Standing on the ground, his horizon is a limited one; and the animals he preys on, if often sharper-eyed and swifter than he, are without intelligence, and thus things are made equal. He can see the rhea as far as the rhea can see him; and if he possessed the eagle's far-seeing faculty it would be of no advantage to him. The high-soaring eagle requires to see very far, but the low-flying owl is near-sighted. And so on through the whole animal world: each kind has sight sufficient to find its food and escape from its enemies, and nothing beyond. Animals that live close to the surface have a very limited sight. Moreover, other faculties may usurp the eye's place, or develop so greatly as to make the eye of only secondary importance as an organ of intelligence. The snake offers a curious case. No other sense seems to have developed in it, yet I take the snake to be one of the nearest-sighted creatures in existence. From long observation of them I am convinced that small snakes of very sluggish habits do not see distinctly farther than from one to three yards. But the snake is the champion faster in the animal world and can afford to lie quiescent until the wind of chance blows something eatable in its way; hence it does not require to see an object distinctly until almost within striking distance. Another remarkable case is that of the armadillo. Of two species I can confidently say that, if they are not blind, they are next door to blindness; yet they are diurnal animals that go abroad in the full glare of noon and wander far in search of food. But their sense of smell is marvellously acute, and, as in the case of the mole, it has made sight superfluous. To come back to man: if, in a state of nature, he is able to guess the character of objects nine times in ten, or nineteen in twenty, seen as far off as he requires to see anything, his intellectual faculties make a better sight unnecessary. If the armadillo's scent had not been so keen and man had not been gifted with nimble brains, the sight in both cases would have been vastly stronger; but the sharpening of its sense of smell has dimmed the armadillo's eyes and made him blinder than a snake; while man (from no fault of his own) is unable to see farther than the wolf and the ostrich and the wild ass.
MECHANISM IN THOUGHT AND MORALS
DR. OLIVER WENDELL HOLMES
[Dr. Holmes was at once a distinguished physician, poet, novelist, and wit. His “Autocrat of the Breakfast Table” is one of the most charming books ever written, his poetry and essays are of even greater popularity. Dr. Holmes's Works are published in fourteen volumes by Houghton, Mifflin & Co., Boston and New York, copyright in various editions. The essay from which extracts follow is in the eighth volume.]
Do we ever think without knowing that we are thinking? The question may be disguised so as to look a little less paradoxical. Are there any mental processes of which we are unconscious at the time, but which we recognize as having taken place by finding certain results in our minds?