César Julien Jean Legallois

Background

Legallois was born on February 1, 1770, in Cherrueix, France, the son of a Breton farmer César Legallois who is said to have worked his land himself. The boy’s mother, Julienne Anne Thérèse Bouassier, died when he was very young, but his father secured him a good education. His father died when Legallois was thirteen.

Education

Legallois was a student at the Collège de Dol; after the death of his father, he received a modest inheritance that he used to further his education. He won first prize in rhetoric at Dol and then began to study medicine at Caen. His career, however, was interrupted once by illness and again, after he recovered, by his involvement as a student leader in an armed movement in support of the federalists. After the defeat of his party, Legallois returned home to escape punishment but was denounced by a relative and fled to Paris. There he remained unnoticed among the crowed of young men trying to learn medicine in the hospitals after the abolition of the medical faculties. He graduated in medicine in 1801 at the École de Médecine de Paris.

Career

Even before his graduation Legallois had acquired great experience in practical medicine through working in hospitals for some ten years. While preparing his dissertation he realized the importance of experimental inquiry. For this reason he devoted much of his energy after he qualified to physiological research, although he had no official position in that field. For about ten years he served as physician to the poor of the twelfth civil district of Paris. He wrote two medicohistorical surveys (one on the discovery of galvanism and one on the chronology of Hippocrates) and a review of data on the contagious nature of yellow fever. He then began a long series of physiological experiments to determine the conditions basic to maintaining the life of any part of the body or, indeed, of the organism as a whole - in short, what he called “the principle of life.”

In spite of his severe myopia and short, thick fingers, Legallois was very skillful in experiments on living animals. His general approach was equally important. He recognized both the possibilities and the limitations of the experimental method as well as the conditions that must be observed to reach valid results. He, therefore, stressed the importance of the choice of animals and the necessity of the controls being of the same species, sex, and age. Legallois thought that life depended on the impression of blood on the brain and the spinal cord, or on a principal resulting from this impression; death was therefore due to the extinction of that principle and might be only partial if the extinction were incomplete.

Legallois was the first to draw attention to variations according to age in the respiratory reactions to the excitation of the central nervous system of animals of the same species.

Legallois died prematurely, about a year after his appointment to the great hospital and asylum of Bicêtre in the outskirts of Paris. He used to walk there from his home every day and in winter, after one such walk, contracted peripneumonia. Well aware of the physiological role of the blood, he refused the usual treatment of the time, bleeding, objecting that his inflammation was of “adynamic” nature, a theory to which some of his biographers believed that he fell victim. Legallois’s notion was, however, sound, although several decades had to pass before the disastrous practice of therapeutic bloodletting was abandoned.

Achievements

• Legallois was the first of the great French Phyiologists who based their conclusions on animal experiments. He is chiefly remembered as the first to localize the respiratory center in the medulla and as one of those who anticipated the internal secretions.

Works

More photos

• book

  • Expériences sur le principe de la vie, notamment sur celui des mouvemens du cœur, et sur le siège de ce principe 1812
  • Oeuvres de César Legallois, médecin en chef de l'hospice et de la prison de Bicêtre 1830

Views

It had already been well accepted that locomotion and motility in general depend on the brain, which determines and regulates all animal functions. Legallois, however, concluded from his experiments that the principle of sensation and motility could only reside in the spinal cord and that the brain is not the unique origin of nervous power. One of his most important achievements was the demonstration of the metameric organization of the spinal cord, by which each segment serves as a center of a specific region, coordinating its sensory and motor activity. The brain thus regulates the movements of the body without supplying the immediate principle; this originates in the spinal cord. The brain acts on the spinal cord in the same way that the spinal cord acts on the muscles, the white matter of the brain being composed of filaments which end in the gray matter of the cord. This gray matter, the origin of the spinal nerves, is the seat of the principle of life.

The mechanics of respiration - those movements which make possible the entry of air into the lungs - depend immediately on the brain; since life is maintained by respiration, the life of the animal depends on the brain, through the medium of the spinal cord. Legallois then, in 1812, convincingly demonstrated that respiratory movements originate in a small area of the medulla oblongata near the occipital foramen and near the level of the origin of the vagus nerves. Indeed, if the cranium of a young rabbit is opened and the brain cut off in serial transverse slices, beginning at the stem, the whole of the cerebrum and of the cerebellum - as well as a part of medulla - can be removed; and respiration ceases suddently only when the lesion reaches the level of the vagus nerves. This effect is not due to the elimination of the vagi, since in an adult animal respiration goes on (although in a somewhat modified form) for a long time after their transsection.

Personality

Legallois was cautious in drawing conclusions from his experiments. In dealing with complex phenomena he tried to isolate the elementary features and thus to determine the general laws of nature. His experiments were remarkable in the diversity and ingenuity of their design and arranged in a logical sequence. Legallois’s unshakable belief in the supreme importance of observations and well-performed experiments, together with his reserve in interpreting his data, indicate that he was a scientist of great stature.

Physical Characteristics: Legallois suffered from severe myopia and had short, thick fingers.

Connections

It is known that Legallois had one son, Eugène Legallois, who was also a doctor. He died in 1831, returning from Poland, as a result of a cholera epidemic.

Father:

César Legallois

Mother:

Julienne Anne Thérèse Bouassier

Son:

Eugène Legallois

References

• Dictionary of Scientific Biography Volume 7
  1973