The experiments of Redi were simple and homely. He exposed meat in jars, some of which were left uncovered, some covered with parchment, and others with fine wire gauze. The meat in all these vessels became spoiled, and flies, being attracted by the smell of decaying meat, laid eggs in that which was exposed, and there came from it a large crop of maggots. The meat which was covered by parchment also decayed in a similar manner, without the appearance of maggots within it; and in those vessels covered by wire netting the flies laid their eggs upon the wire netting. There they hatched, and the maggots, instead of appearing in the meat, appeared on the surface of the wire gauze. From this Redi concluded that maggots arise in decaying meat from the hatching of the eggs of insects, but inasmuch as these animals had been supposed to arise spontaneously within the decaying meat, the experiment took the ground from under that hypothesis. He made other observations on the generation of insects, but with acute scientific analysis never allowed his conclusions to run ahead of his observations. He suggested, however, the probability that all cases of the supposed production of life from dead matter were due to the introduction of living germs from without. The good work begun by Redi was confirmed and extended by Swammerdam (1637-1681) and Vallisnieri (1661-1730), until the notion of the spontaneous origin of any forms of life visible to the unaided eye was banished from the minds of scientific men. [Illustration: Fig. 89.--Francesco Redi, 1626-1697.] Redi (Fig. 89) was an Italian physician living in Arentino, distinguished alike for his attainments in literature and for his achievements in natural science. He was medical adviser to two of the grand dukes of Tuscany, and a member of the Academy of Crusca. Poetry as well as other literary compositions shared his time with scientific occupations. His collected works, literary, scientific, and medical, were published in nine octavo volumes in Milan, 1809-1811. This collection includes his life and letters, and embraces one volume of sonnets. The book that has been referred to as containing his experiments was entitled _Esperienze Intorno Alla Generazione Degl'Insetti_, and first saw the light in quarto form in Florence in 1668. It went through five editions in twenty years. Some of the volumes were translated into Latin, and were published in miniature, making books not more than four inches high. Huxley says: "The extreme simplicity of his experiments, and the clearness of his arguments, gained for his views and for their consequences almost universal acceptance."