In addition to the phenomena which spring from the intelligence and reasoning, we find in animals other impulses which arise from _Instinct_, a blind impulse, or at least apparently so, which often is the characteristic of animal species, and with which each individual is endowed. These two orders of facts are very often confounded, but the confusion can be explained as follows. In the first place, instinct has as its object the attainment of a determined and fixed result, but in the multitude of ways and means necessary to attain this result a portion which is often very large is due to the intelligence. The distinction is not always easy. It will, moreover, be apparent that I cannot here enter into the details required by the examination of this question, so entirely foreign to that which is before us. Besides the acts of intelligence and instinct, phenomena have been established among animals which are closely connected with what we call _character_, _sentiment_, or _passion_. The familiarity of the terms is in itself a proof that upon this point ordinary observation has outstripped scientific examination. All these phenomena are perfectly new and have no analogy with those which we have noticed in the preceding kingdoms. They evidently justify the formation of an equally important group. The _animal kingdom_ is thus universally admitted, independently of every theory which attempts to explain its characters. Facts radically different cannot be attributed to the same cause. We must admit, then, that the characteristic phenomena of the animal depend upon something different to those met with in the vegetable or mineral kingdoms. They are, moreover, united by such intimate relations, that it would be impossible not to attribute them to a single cause. From motives already mentioned we will give a name to this _Unknown Cause_, and, making use of an expression already established, though open, I can see, to more than one criticism, we will call it the _Animal Mind_ (l’âme animale). Does the animal mind liberate the beings it animates from the inferior forces? By no means, for we find them repeated with all their characteristics. In order to raise the least of its organs, the animal must contend with weight; it cannot perform the smallest movement without the intervention of physico-chemical phenomena; it cannot breathe, and, therefore, cannot live, without constantly consuming some of its constituents. In the animal, moreover, just as much as in the plant, the inanimate forces, etherodynamy especially, appear in their double character of constancy and of ubiquity in the accomplishment of phenomena, and of subordination to life, which governs their action in the animal as in the plant.