Life and death

by A. Dastre

This distinction agrees with the fact of the diffusion of life. Life does not belong to the superior animals alone, and to the man in whom we can recognize a reasoning soul. It is extended to the vast multitude of humbler beings to which such lofty faculties cannot be attributed, the invertebrates, microscopic animals, and plants. The advantage is compensated for by the inconvenience of breaking down all continuity between the soul and life; a continuity which is the principle of the two other doctrines, animism and monism, and which is, we may say, the very aim and the unquestionable tendency of science.

As for classical philosophy, it satisfies the necessity of establishing the unity of the living being,—i.e., of bringing into harmony soul and body,—but in a manner which we need not here discuss. It attributes to the soul several modalities, several distinct powers: powers of the vegetative life, powers of the sensitive life, and powers of the intellectual life. And this other solution of the problem would be, in the opinion of M. Gardair, in complete agreement with the doctrines of St. Thomas Aquinas.

§ 1. The Vitalism of Barthez: its Extension.

Vitalism reached its most perfect expression in the second half of the eighteenth century in the hands of the representatives of the Montpellier school—Bordeu, Grimaud, and Barthez. The last, in particular, contributed to the prevalence of the doctrine in medical circles. A man of profound erudition, a collaborates with d’Alembert in the Encyclopædia, he exercised quite a preponderant influence on the medicine of his day. Stationed at Paris during part of his career, physician to the King and the Duke of Orleans, we may say that he supported his theories by every imaginable influence which might contribute to their success. In consequence of this, the medical schools taught that vital phenomena are the immediate effects of a force which has no analogues outside the living body. This conception reigned unchallenged up to the days of Bichat.

After Bichat, the vitalism of Barthez, more or less modified by the ideas of the celebrated anatomist, continued to hold its own in all the schools of Europe until about the middle of the nineteenth century. Johannes Müller, the founder of physiology in Germany, admitted, about 1833, the existence of a unique vital force “aware of all the secrets of the forces of physics and chemistry, but continually in conflict with them, as the supreme cause and regulator of all phenomena.” When death came, this principle disappeared and left no trace behind. One of the founders of biological chemistry, Justus Liebig, who died in 1873, shared these ideas. The celebrated botanist, Candolle, who lived up to 1893, taught at the beginning of his career that the vital force was one of the four forces ruling in nature, the other three being—attraction, affinity, and intellectual force. Flourens, in France, made the vital principle one of the five properties of forces residing in the nervous system. Another contemporary, Dressel, in 1883, endeavoured to bring back into fashion this rather primitive, monistic, and efficient vitalism.

The Seat of the Vital Principle.—Meanwhile, another question was asked with reference to this vital principle. It was a question of ascertaining its seat: or, in other words, of finding its place in the organism. Is it spread throughout the organism, or is it situated in some particular spot from which it acts upon every part of the body? Van Helmont, a celebrated scientist at the end of the sixteenth century, who was both physician and alchemist, gave the first and rather quaint solution of this difficulty. The vital principle, according to him, was situated in the stomach, or rather in the opening of the pylorus. It was the concierge, so to speak, of the stomach. The Hebrew idea was more reasonable. The life was connected with the blood, and was circulated with it by means of all the veins of the organism. It escaped from a wound at the same time as the liquid blood. It is clear that in this belief we see why the Jews were forbidden to eat meat which had not been bled.

The Vital Knot.—In 1748 a doctor named Lorry found that a very small wound in a certain region of the spinal marrow brought on sudden death. The position of this remarkable point was ascertained in 1812 by Legallois, and more accurately still by Flourens in 1827. It is situated in the rachidian bulb, at the level of the junction of the neck and the head; or more precisely, on the floor of the fourth ventricle, near the origin of the eighth pair of cranial nerves. This is what was called the vital knot. Upon the integrity of this spot, which is no bigger than the head of a pin, depends the life of the animal. Those who believed in a localisation of the vital principle thought that they had found the seat desired; but for that to be so the destruction of this spot must be irremediable, and must necessarily cause death. But if the vital knot be destroyed, and respiration be artificially induced by means of a bellows, the animal resists: it continues to live. It is only the nervous stimulating mechanism of the respiratory movements which has been attacked in one of its essential parts.

Life, therefore, resides no more in this point than it does in the blood or in the stomach. Later experiment has shown that it resides everywhere, that each organ enjoys an independent life. Each part of the body is, to use Bordeu’s strong expression, “an animal in an animal”; or to adopt the phrase due to Bichat, “a particular machine within the general machine.”

The Vital Tripod.—What then is life, or, in other words, what is the biological activity of the individual, of the animal, of man? It is clearly the sum total, or rather, the harmony of these partial lives of the different organs. But in this harmony it seems that there are certain instruments which dominate and sustain the others. There are some whose integrity is more necessary to the preservation of existence and health, and of which any lesion makes death more inevitable. They are the lungs, the heart, and the brain. Death always ensues, said the early doctors, if any one of these three organs be injured. Life depends, therefore, on them, as if upon a three-legged support. Hence the idea of the vital tripod. It is no longer a single seat for the vital principle, but a kind of throne on three-supports. Life is decentralized.

This was only the first step, very soon followed by many others, in the direction of vital decentralization. Experiment showed, in fact, that every organ separated from the body will continue to live if provided with the proper conditions. And here, it is not only a question of inferior beings; of plants that are propagated by slips; of the hydra which Trembley cut into pieces, each of which generated a complete hydra; of the naïs which C. Bonnet cut up into sections, each of which reconstituted a complete annelid. There is no exception to the rule.