“The general movements of the nervous fluid are of two kinds; namely,
“1. Partial movements (ébranlements), which finally become general and end in a reaction. It is the movements of this sort which produce feeling. We have treated of them in the third chapter.
“2. The movements which are general from the time they begin, and which form no reaction. It is these which constitute internal emotions, and it is of them alone of which we shall treat.
“But previously, it is necessary to say a word regarding the feeling of existence, because this feeling is the source from which the inner emotions originate.
“On the Feeling of Existence.
“The feeling of existence (sentiment d’existence), which I shall call inner feeling,[183] so as to separate from it the idea of a general condition (généralité) which it does not possess, since it is not common to all living beings and not even to all animals, is a very obscure feeling, with which are endowed those animals provided with a nervous system sufficiently developed to give them the faculty of feeling.
“This sentiment, very obscure as it is, is nevertheless very powerful, for it is the source of inner emotions which test (éprouvent) the individuals possessing it, and, as the result, this singular force urges these individuals to themselves produce the movements and the actions which their wants require. Moreover this feeling, considered as a very active motor, only acts thus by sending to the muscles which necessarily cause these movements and actions the nervous fluid which excites them....
“Indeed, as the result of organic or vital movements which are produced in every animal, that which possesses a nervous system sufficiently developed has physical sensibility and continually receives in every inner and sensitive part impressions which continually affect it, and which it feels in general without being able to distinguish any single one.
“The sentiment of existence [consciousness] is general, since almost every sensitive part of the body shares in it. ‘It constitutes this me (moi) with which all animals, which are only sensitive, are penetrated, without perceiving it, but which those possessing a brain are able to notice, having the power of thought and of giving attention to it. Finally, it is in all the source of a power which is aroused by wants, which acts effectively only by emotion, and through which the movements and actions derive the force which produces them’....
“Finally, the inner feeling only manifests its power, and causes movements, when there exists a system for muscular movement, which is always dependent on the nervous system, and cannot take place without it.”
The author then states that these emotions of the organic sense may operate in the animals and in man either without or with an act of their will.
“From what has been said, we cannot doubt but that the inner and general feeling which urges the animals possessing a nervous system fitted for feeling should be susceptible of being aroused by the causes which affect it; moreover, these causes are always the need both of satisfying hunger, of escaping dangers, of avoiding pain, of seeking pleasure, or that which is agreeable to the individual, etc.
“The emotions of the inner feeling can only be recognized by man, who alone pays attention to them, but he only perceives those which are strong, which excite his whole being, such as a view from a precipice, a tragic scene, etc.”
Lamarck then divides the emotions into physical and moral, the latter arising from our ideas, thoughts—in short, our intellectual acts—in the account of which we need not follow him.
In the succeeding chapter (V.) the author dilates on the force which causes actions in animals. “We know,” he says “that plants can satisfy their needs without moving, since they find their food in the environing milieux. But it is not the same with animals, which are obliged to move about to procure their sustenance. Moreover, most of them have other wants to satisfy, which require other kinds of movements and acts.” This matter is discussed in the author’s often leisurely and prolix way, with more or less repetition, which we will condense.
The lowest animals—those destitute of a nervous system—move in response to a stimulus from without. Nature has gradually created the different organs of animals, varying the structure and situation of these organs according to circumstances, and has progressively improved their powers. She has begun by borrowing from without, so to speak—from the environment—the productive force, both of organic movements and those of the external parts. “She has thus transported this force [the result of heat, electricity, and perhaps others (p. 307)] into the animal itself, and, finally, in the most perfect animals she has placed a great part of this force at their disposal, as I will soon show.”
This force incessantly introduced into the lowest animals sets in motion the visible fluids of the body and excites the irritability of their contained parts, giving rise to different contractile movements which we observe; hence the appearance of an irresistible propensity (penchant) which constrains them to execute those movements which by their continuity or their repetition give rise to habits.
The most imperfect animals, such as the Infusoria, especially the monads, are nourished by absorption and by “an internal inhibition of absorbed matters.” “They have,” he says, “no power of seeking their food, they have not even the power of recognizing it, but they absorb it because it comes in contact with every side of them (avec tous les points de leur individu), and because the water in which they live furnishes it to them in sufficient abundance.”
“These frail animals, in which the subtile fluids of the environing milieux constitute the stimulating cause of the orgasm, of irritability and of organic movements, execute, as I have said, contractile movements which, provoked and varied without ceasing by this stimulating cause, facilitate and hasten the absorptions of which I have just spoken.” ...