The comparative psychology of peoples, studied from this point of view, certainly does not include the whole of psychological science, which requires other instruments and other modes of experience, but it is a great help as a foundation.  We believe that the study of myth, which throws so much light on comparative psychology, is likewise of use for the special psychology of man, since this can only arise from individual and ethnical observation, and from experiment, dissociated from every hindrance, and from metaphysical prejudice.  And if by our humble essay we can throw any light on this noble science, we shall be abundantly rewarded.

CHAPTER II.

ANIMAL SENSATION AND PERCEPTION.

All animals communicate with each other and with the external world through their senses, and by means of their perception, both internal and external, they possess knowledge and apprehension of one another.  In the vast organic series of the animal kingdom, some are better provided than others with methods, instruments, and apparatus fit for effecting such communication.  The senses of relation are not found in the same degree in all animals, nor when such senses are the same in number are they endowed with equal intensity, acuteness, and precision.  But the fundamental fact remains the same in all cases; they communicate with themselves and with the external world through their senses.

We must now inquire what value the external object of perception, considered in itself, has for the animal, what character it has and assumes with respect to his inner sense in the act of perception or apprehension.  Man, and especially man in our days, after so many ages of reflection, and through the influence of contemporary science, is so far removed from the primitive and simple exercise of his psychical life, that he finds it difficult to picture to himself the ancient and spontaneous conditions under which his senses communicated with the world and with himself.  And therefore, without further consideration, he thinks and believes that in primeval times everything took place in the same way as it does at present, and, which is a still greater error, as it takes place in the lower animals.

This identification of the complex machinery of human perception with that of animals must not be regarded as an absurd paradox, since, as we have shown in an earlier work, they were originally and in themselves the same.[8] By pursuing an easy mode of observation, divested of prejudice, we may revert to that primeval state of human nature, and may also comprehend with truth and certainty the condition of animals.  For the animal nature has not ceased to exist in man, and it may be discerned by those who care to look for it; and careful study, with the constant aid of observation and experiment, will reveal to us the hidden life of sensation and intelligence in the lower animals.