Resumen

WISNIAK, Jaime. JEAN-AUGUSTIN BARRAL. Rev. CENIC Cienc. Biol [online]. 2024, vol.55, pp. 59-69.  Epub 25-Abr-2024. ISSN 2221-2450.

Jean-Augustin Victor Barral (1819-1884), a French agronomist, chemist, and physicist, was the first to extract nicotine (tobacco alkali) from the leaves of the plant, analyze it, determine its formula, and demonstrate experimentally that it was a violent poison. It turned blue wet litmus paper and behaved like a fixed alkali. Barral studied extensively the question of chemical balance of living animals and carried the pertinent chemical analysis balance of the solid and liquid foods ingested daily and the amount and elemental composition of the diverse evacuations, transpiration, and excretions, to establish the gain and loss equations of the body. He also carried a heat balance of the same systems. He conducted most of the pertinent experiments on himself and his son, and on sheep. Particular interest was put on the role played by sodium chloride in human and animal economy. This was carried by a careful analysis of the chlorine content of the different streams. He found that the quantity of nitrogen present in the food was higher than that in the evacuations, so that a part of the gas had to be exhaled by perspiration. Also, the evacuations were richer in hydrogen than food in the ratio 1 to 5. Barral studied the composition of rainwater and its influence on vegetation and determined the yearly amounts of nitrogen, ammonia, nitric acid, chlorine, lime, and magnesium that it contributed to the chemical balance of the soil. Barral also carried a detailed experimental analysis of the gilding process and determined the best conditions for performing the art. He also extended the experimental results of Arago and Ampère about the electro-magnetization. Barral's name is one of the 72 names of scientists that Eiffel inscribed in his tower.

Palabras clave : body balance; sodium chloride; gilding; nicotine; rainwater.