Ingenhouz, John

, an eminent physician and chemist, was born at Breda in 1730. In 1767 he came to England with a view of obtaining information on the Suttonian method of inoculation for the small-pox, and in the following year he went, on the recommendation of the late sir John Pringle, to Vienna, to inoculate the archduchess Theresa- Elizabeth, only daughter of Joseph II. and the archdukes Ferdinand and Maximilian, brothers of the emperor. For these services he obtained rewards and honours: he was made body-physician aJid counsellor of state to their imperial majesties, with a pension of 600l. per annum. In the following spring he went to Italy, and inoculated the grand duke of Tuscany. After this he returned to England, to which he was much attached, where he spent his time in scientific pursuits. He published a very valuable work, entitled “Experiments on Vegetables, discovering their great power of purifying the common air in sunshine, but injuring it in the shade or night.” This work was first published in 1779, and was translated into the French and German languages, and highly esteemed by all the experimental philosophers of that period. He ascertained, that not only from the green matter found on stagnant waters, but likewise from the leaves of vegetables, from the green branches and shoots, even from the entire vegetable, when placed under water and exposed to the solar light, oxygen gas, in a state generally of great purity, is evolved; and as the result of his numerous experiments he adopted the conclusion, that oxygen is elaborated in the leaves and other organs of vegetables, by a vital action excited and sustained by the solar light. The doctor, through the whole of life, was fond of exhibiting among his friends, particularly young persons, experiments of | this kind, which required scarcely any apparatus, excepting a bell glass and a phial or two; and with the oxygen gas which he obtained from cabbage-leaves or other vegetables, he would exhibit the combustion of iron-wire, which is a striking and very brilliant experiment. Dr. Ingenhouz was author of many papers inserted in the Transactions of the Royal Society, of which body he was an active and useful member. Of these papers we may notice the following: Experiments on the Torpedo. Methods of measuring the diminution of bulk taking place on the mixture of nitrous with common air. Experiments on the Electrophorus. New Methods of suspending Magnetic Needles. Considerations on the influence of the Vegetable Kingdom on the Animal Creation. He died in 1799, highly esteemed for the simplicity of his manners, and for the discoveries which he had made in the several departments of experimental philosophy. 1


Rees’s Cyclopædia.—Murray’s Chemistry.—Nichols’s Bowyer, vol. VIII.