Biography of Jan Ingenhousz (1730-1799)

Physiologist and chemist Dutch, discoverer of the process of photosynthesis in plants, for which plants, in the presence of light, produce organic substances from other inorganic, and release oxygen into the atmosphere during the process.

Born in Breda 8 December 1730, and died in the English City of Bowood (Wiltshire), on September 7, 1779. Son of a leather merchant, were encouraged to study medicine encouraged by a prestigious British doctor, John Pringle. He/She studied in his hometown, also in Leiden, and subsequently completed studies in Paris and Edinburgh, to return again to Breda, where he/she worked as a doctor in a private practice.

He subsequently moved to England and worked in a hospital, in which put into practice measures to prevent epidemics of smallpox, which consisted in inoculating patients with small amounts of live virus and not modified. In 1768 he/she moved to Vienna to practise this inoculation to the Austrian Royal family and later worked as a doctor of the Court, where he/she served for more than ten years.

After his stay in Austria, he/she returned to London, and here Ingenhousz began to be interested in the oxygen produced by plants. Gas had been discovered by Joseph Priestley in 1774 and both noted that green plants give off oxygen and need light to grow. Ingenhousz devised a series of procedures and performed hundreds of experiments to measure the amount of oxygen consumed and detached by plants in the process of breathing, and in 1779 showed that plants remove carbon dioxide (CO2 in the dark). In addition, he/she found that the amount of oxygen, slipped during the day was less than the amount of CO2 from the night; and it is that photosynthesis helps the plant use CO2 to grow. One of his experiments was to demonstrate that when the plants are immersed in water they emit little bubbles, and deduced that the cause of this phenomenon was indirectly the sunlight. Several publications recorded their results: Experiments Upon Vegetables, Discovering Their Great Power of Purifying the Common Air in Sunshine, and Injuring It in the Shade and at Night. His works established the necessary basis so then all the steps of photosynthesis would be determined with precision.

In addition and irrespective of the plants, he/she perfected in 1766 a device to generate large amounts of static electricity. And in 1789, he/she made the first quantitative measurements on conduction and propagation of heat in the metal bodies.