[129] Henri Louis du Hamel du Monceau was born at Paris in 1700 and died in 1781. He had an estate in the Gatinais, and turned his studies in physics, chemistry, zoology, and botany to account in the composition of a number of treatises on agriculture, the management of woods and forests, naval affairs, and fisheries. He was made Member of the Academy in 1728 on presenting to it an essay on a disease then raging in the saffron-plantations, and caused by the growth of a fungus (‘Biographie Universelle’).
[130] See Kopp, ‘Geschichte der Chemie’ (1843), i. p. 306, and ‘Entwicklung der Chemie in der neucrenzeit’ (1873), p. 138.
[131] Still less was gained from an observation made by Bonnet, that leaves exposed to sun-light in water containing air show bubbles of gas on their upper surface. Bonnet expressly denied the active participation of the leaves in the phenomenon, since the same thing happens with dead leaves in water containing air.
[132] Jan Ingen-Houss, physician to the Emperor of Austria, practised first in Breda, and afterwards in London. He was born at Breda in Holland in 1730, and died near London in 1799.
[133] Jean Senebier, born at Geneva in 1742, was the son of a tradesman, and after 1765 pastor of the Evangelical Church. On his return from a visit to Paris he published his ‘Moral Tales,’ and at the suggestion of his friend Bonnet competed for a prize offered at Haarlem for an essay on the Art of Observation. He was awarded the second place in this competition. In 1769 he became pastor at Chancy, and in 1773 librarian of Geneva. At this time, among other literary labours, he translated Spallanzani’s more important writings; he also studied chemistry under Tingry, and carried out his researches into the influence of light. In 1791 he wrote an article for the ‘Encyclopaedie méthodique’ on vegetable physiology. The revolution in Geneva drove him into the Canton Vaud, and there he composed his ‘Physiologie végétale,’ in five volumes. He returned to Geneva in 1799 and took part in a new translation of the Bible. He died in that city in 1809 (‘Biographie Universelle’).
[134] Nicolas Théodore de Saussure was born at Geneva in 1767, and died there in 1845. He was the son of the famous explorer of the Alps, and assisted his father in his observations on Mont Blanc and the Col du Géant. In 1797 he wrote his treatise on carbonic acid in its relation to vegetation, a prelude to his ‘Recherches chimiques’; the latter work received great attention from the scientific world, and he was made a corresponding member of the French Institute. He was a man of literary tastes, and took part also in public affairs, being repeatedly elected to the Council of Geneva. His preference for a secluded life is said to have been the reason why he never undertook the duties of a professorship. See the supplement to the ‘Biographie Universelle’ and Poggendorf’s ‘Biographisch-litterarisches Handwörterbuch.’
[135] Henri Joachim Dutrochet, born in 1776, was a member of a noble family which belonged to the department of the Indre and lost its property during the revolution; he therefore adopted medicine as a profession, and took his degree at the Faculty of Paris in 1806. He was attached to the armies in Spain as military surgeon in 1808 and 1809; but he retired as soon as possible from practice and devoted himself in great seclusion to his physiological pursuits, living for some years in Touraine. He was made corresponding member of the Academy in 1819, and communicated his discoveries to that body. Becoming an ordinary member in 1831, he spent the winter months from that time forward in Paris. He died in 1847 after two years’ suffering from an injury to the head. Dutrochet was one of the most successful champions, in animal as well as vegetable physiology, of the modern ideas which displaced the old vitalistic school of thought after 1820. See the ‘Allgemeine Zeitung’ for 1847, p. 780.
[136] See above on page 513.
[137] Thomas Andrew Knight, President of the Horticultural Society, was born at Wormsley Grange, near Hereford, in 1758, and died in London in 1838.
[138] See ‘Arbeiten des botanischen Institutes in Würzburg,’ vol. i. p. 99.