Laws of Animality

Appendix 2. (1926).

Allow me to use Dr. Broussais' words to describe the multiple sense-experiences which accompany hunger and nutrition, together with the multiple actions which go with them and successively produce them. It is this complex of feelings and actions which constitutes the digestive or nutritional function.

Feeling which is not limited to the period in which the stomach is empty, but in convalescence continues during digestion, shows that all the tissues of the body in which the living chemical is exercised have a corresponding relationship with the stomach. The disposition of the branches of the great sympathetic nerve which converges on the stomach show how this correspondence takes place. The sensation of pain at the epigastrum indicates the mucous membrane as seat of the internal sense from which the brain receives the perception of hunger. As soon as this membrane is touched by food, the sensation disappears. Concomitant pain and weakness in the muscles during hunger, and concomitant pleasure, force and aptitude for action in these tissues as soon as hunger is appeased, make us realise that the stomach suffers and delights along with the whole locomotive apparatus, or better, that the perception of pain or pleasure in the gastric sense is accompanied by analogous perception in the muscular system.

Sadness, joy, anger, which go hand in hand with the pain and pleasure of which we are speaking, make us realise that myself is drawn towards its judgments by the sensation of pain or pleasure it receives from the internal gastric sense and from the tissues which share its modifications. The calm in circulation during hunger shows that the forces are directed towards the relationship-apparatus whose action is necessary if our need is to be satisfied. The slight chill which follows a meal indicates a moment in which the forces are called to concur in digestion. Excitation of the heart and acceleration of the circulation, which goes hand in hand with the frequency of the acts of breathing, bear witness to the influence of the stomach on the lungs and the heart. This influence is further demonstrated by an increase of the mucous secretion of the lungs rather than by the acceleration of respiration.

This acceleration is also produced by muscular exercise, a sure sign that it depends always upon an abundance of blood reaching the lungs. I have often observed that despite a full stomach, breathing is not accelerated unless digestion is in full activity. Finally, torpor and sleep, which indicate the final cessation of gastric excitation, show that forces have to a great extent already left and abandoned the organs of the interior life, and that the brain, sharing in their modification by means of its vascular system, suffers some compression which temporarily suspends the exercise of intelligence

(Réfléxions sur les functions du système nerveux en général, etc. Journal universel des sciences médicales, November 1818).

This beautiful description (in which certain inexact expressions can be ignored) shows how feeling presides over the entire function of nutrition.