I ought not, perhaps, to pass over in perfect silence the subject of protozoan psychology. M. Binet has published a little book on "The Psychic Life of Micro-Organisms," in the preface of which he says, "We could, if it were necessary, take every single one of the psychical faculties which M. Romanes reserves for animals more or less advanced on the zoological scale, and show that the _greater part_ of these faculties belonged equally to micro-organisms." He says that "there is not a single infusory that cannot be frightened, and that does not manifest its fear by a rapid flight through the liquid of the preparation," and he speaks of infusoria fleeing "in all directions like a flock of frightened sheep." He attributes memory to _Folliculina_, and instinct "of great precision" to _Difflugia_. He regards some of these animalculæ as "endowed with memory and volition," and he describes the following stages:-- "1. The perception of the external object. "2. The choice made between a number of objects. "3. The perception of their position in space. "4. Movements calculated either to approach the body and seize it or to flee from it." But when we have got thus far, we are brought up by the following sentence: "We are not in a position to determine whether these various acts are accompanied by consciousness, or whether they follow as simple physiological processes." Since, therefore, the fear, memory, instinct, perception, and choice, spoken of by M. Binet, may be merely physiological processes (though, of course, they _may be_ accompanied by some dim unimaginable form of consciousness), it seems scarcely necessary to say more about them here. * * * * * I have now said all that is necessary, and all that I think justified by the modest scope of this work, concerning the process of construction in animals, and the nature of the constructs we may presume that they form. The process I hold to be similar in kind throughout the animal kingdom wherever we may presume that it occurs at all. But the products of the process seem to me to be presumably widely different. If we steadily bear in mind the fact that the world of man is a joint product of an external existence and the human mind, and then ask whether it is conceivable that the joint products of this external existence and the dog-mind, the bird-mind, the fish-mind, the bee-mind, or the worm-mind are exactly or even closely similar, we must, it seems to me, answer the question with an emphatic negative. * * * * * We will now consider the nature of the inferences of animals. It will be remembered that a distinction was drawn between perceptual inferences and inferences involving a conceptual element. As I use the words, perceptual inferences are a matter, at most, of intelligence; but conceptual inferences involve the higher faculty of reason.