BY C. LLOYD MORGAN, F.G.S., PROFESSOR IN AND DEAN OF UNIVERSITY COLLEGE, BRISTOL; LECTURER AT THE BRISTOL MEDICAL SCHOOL; PRESIDENT OF THE BRISTOL NATURALISTS' SOCIETY, ETC. AUTHOR OF "ANIMAL BIOLOGY," "THE SPRINGS OF CONDUCT," ETC. BOSTON, U. S. A. GINN & COMPANY, PUBLISHERS. 1891. TO MY FATHER....

There are many books in our language which deal with Animal Intelligence in an anecdotal and conventionally popular manner. There are a few, notably those by Mr. Romanes and Mr. Mivart, which bring adequate knowledge and training to bear on a subject of unusual difficulty. In the following pages I have endeavoured to contribute something (imperfect, as I know full well, but the result of several years' study and thought) to our deeper knowledge of those mental processes which we may fairly infer

I once asked a class of school-boys to write down for me in a few words what they considered the chief characteristics of animals. Here are some of the answers— Combining these statements, we have the following characteristics of animals:— Now, let us look carefully at these characteristics, all of which were contained in the five answers, and were probably familiar in some such form as this to all the boys, and see if we cannot make them more general and more accurate. 1. An animal has a defini

In the foregoing chapter, on "The Nature of Animal Life," we have seen that animals breathe, feed, grow, are sensitive, exhibit various activities, and reproduce their kind. These may be regarded as primary life-processes, in virtue of which the animal characterized by them is a living creature. We have now to consider some of these life-processes—the sum of which we may term the process of life—a little more fully and closely. The substance that exhibits these life-processes is protoplasm, whic

We have now to turn to a fresh aspect of animal life, that of reproduction; and it will be well to connect this process as closely as possible with the process of life in general, of which it is a direct outcome. It will be remembered that, in the last chapter, it was shown that the essential feature in the process of life is the absorption by living protoplasm of oxygen on the one hand and nutritive matter on the other hand, and the kneading of these together, in subtle metabolism, into unstabl

Everything, so far as in it lies, said Benedict Spinoza, tends to persist in its own being. This is the law of persistence . It forms the basis of Newton's First Law of Motion, which enunciates that, if a body be at rest, it will remain so unless acted on by some external force; or, if it be in motion, it will continue to move in the same straight line and at a uniform velocity unless it is acted on by some external force. Practically every known body is thus affected by external forces; but the

The law of heredity, I have said above, may be regarded as that of persistence exemplified in a series of organic generations. Variation results—it is clear that it must result—from some kind of differentiating influence. Such statements as these, however, though they are true enough, do not help us much in understanding either heredity or variation. Let us first notice that normal cases of reproduction exemplify both phenomena—heredity with variation; hereditary similarity to the parents in all

Natural selection claims a foremost place. We have already devoted a chapter to its consideration. Animals vary; more are born than can survive to procreate their kind; hence a struggle for existence, in which the weaker and less adapted are eliminated, the stronger and better adapted surviving to continue the race. It is scarcely possible to over-estimate what Darwin's labour and genius have done for the study of animal life. Through Darwin's informing spirit, biology has become a science. But

We may now pass on to consider shortly some of the phenomena of degeneration, and the dwindling or disappearance of structures which are no longer of use. Many zoologists believe, or until lately have believed, that disuse is itself a factor in the process. Just as the well-exercised muscle is strengthened, so is the neglected muscle rendered weak and flabby. Until recently it was generally held that the effects of such use or disuse are inherited. But now Professor Weismann has taught us, if no

It is well known that, in addition to and apart from the primary sexual differences in animals, there are certain secondary characters by which the males, or occasionally the females, are conspicuous. The antlers of stags, the tail of the peacock, the splendid plumes of the male bird of paradise, the horns or pouches of lizards, the brilliant frilled crest of the newt, the gay colours of male sticklebacks, the metallic hues of male butterflies, and the large horns or antennæ of other insects,—th

As we have already seen, biologists are divided into two schools, one of which maintains that the effects of use and disuse [DE] have been a potent factor in organic evolution; the other, that the effects of use and disuse are restricted to the individual. My own opinion is that we have not a sufficient body of carefully sifted evidence to enable us to dogmatize on the subject, one way or the other. But, the position of strict equilibrium being an exceedingly difficult and some would have us bel

The diversity of the variations which are possible, and which actually occur in animal life, is so great that it is not easy to sum up in a short space the nature of variations. Without attempting anything like an exhaustive classification, we may divide variations into three classes. 1. Superficial variations in colour, form, etc., not necessarily in any way correlated with 2. Organic variations in the size, complexity, and efficiency of the organs of the body; 3. Reproductive and developmental

Given the occurrence of variations in certain individuals of a species, we have the alternative logical possibilities of their being inherited or their not being inherited. The latter alternative seems at first sight to be in contradiction to the law of persistence. Sir Henry Holland, seeing this, remarked that the real subject of surprise is, not that a character should be inherited, but that any should ever fail to be inherited. [DS] Intercrossing may diminish a character, and sooner or later

The subject of the origin of variations is a difficult one, one concerning which comparatively little is known, and one on which I am not able to throw much light. Taking a simple animal cell as our starting-point, we have already seen that it performs, in primitive fashion, certain elementary and essential protoplasmic activities, and gives rise to certain products of cell-life. In the metazoa, which are co-ordinated aggregates of animal cells, together with some of their products, there is see

It only remains to bring this chapter to a close with a few words of summary and conclusion. The diversity of animal life must first be grasped. We believe that this diversity is the result of a process or processes of evolution. Evolution is the term applied to continuity of development. It involves adaptation; and adaptation to an unchanging environment may become more and more perfect. But the environment to which organisms are adapted also changes. Where the change is in the direction of com

It is part of the essential nature of an animal to be receptive and responsive. The forces of nature rain their influence upon it; and it reacts to their influence in certain special ways. Other organisms surround it, compete with it, contend with it, strive to prey upon it, and occasionally lend it their aid. It has to adjust itself to this complex environment. There are two kinds of organic response—one more or less permanent, the other temporary and transient. We have already seen something o

I have already drawn attention to the fact that the primary end and object of the reception of the influences ( stimuli ) of the external world, or environment, is to enable the organism to answer or respond to these special modes of influence, or stimuli. In other words, their purpose is to set agoing certain activities. Now, in the unicellular organism, where both the reception and the response are effected by one and the same cell, the activities are for the most part simple, though even amon

Two things I have been especially anxious to bring out prominently in the foregoing chapter: first, that the world we see around us is a joint product of two factors—the outward existence, on the one hand, and our active mind on the other; and secondly, that our mental processes and products fall under two categories—on the one hand, perception, giving rise to percepts, perceptual inferences, and intelligence, and on the other, conception (involving the analysis of phenomena), giving rise to con

There is one aspect of the mental processes of men and animals that we have so far left unnoticed—the aspect of feeling, the aspect of pleasure and pain. Quite distinct from, and yet intimately associated with, our perception of a beautiful scene, is the pleasure we derive therefrom; and quite distinct from, and yet inseparably bound up with, our perception of a discordant clang, is the painful effect that it produces. We have, however, no separate organs for the appreciation of pleasure and pai

So soon as one of the higher animals comes into the world a number of simple vital activities are already in progress or are at once initiated. Some of these are what are termed "automatic actions," or actions which take their origin within the organ which manifests the activity; such are the heart-beat and the rhythmical contractions of the intestines by which the food is pushed onwards through the alimentary canal. Some are reflex, or responsive, actions, taking origin from a stimulus coming f