Francesco Redi (1626-1698)
Born in Arezzo, Francesco Redi studied in the Jesuit school in Florence and graduated in medicine from Pisa in 1647. After some trips to Rome, Naples, Bologna, Padua and Venice, he began to work in medicine. In 1666 he was appointed Chief Physician by the Grand Duke Ferdinando II and was responsible for the granducal "spezieria" [pharmacy] and "fonderia" [foundry], a job which was also assigned to him by Cosimo III (1642-1723) and which he kept until his death, embodying the classic example of a scientist and courtier. He effectively applied himself to the natural sciences and the Accademia del Cimento's experimentalism. His first scientific work was Osservazioni intorno alle vipere [Observations concerning vipers] (Florence, 1664) [fig.1]. Addressed to Lorenzo Magalotti, this was a memoir about how he found the location of the viper's poison, clarifying the way in which it wielded its toxins. Redi's true masterpiece, destined to signal a milestone in the history of modern science, was his Esperienze intorno alla generazione degl'insetti [Experiments concerning the generation of insects] (Florence, 1668) [fig.2]. In this work, dedicated to Carlo Dati, he refuted the age-old theory of spontaneous generation of insects and parasites with a telling experiment, which introduced into the scientific method a serial procedure and a comparison between experimental research and controlled experiments. He prepared eight receptacles filled with various types of meat, four of which were left in open air while the others were carefully sealed. The result was unequivocal: only the first specimens, upon which flies stopped to lay their eggs on the flesh, provided a source for grubs that then developed into flies. Meanwhile, the meat in the sealed containers became putrid, but without generating any form of life. Furthermore, to avoid that the hermetic closure of the receptacles impeding the influx of air should alter the grub's life cycle, Redi produced a variation, utilising two other identical series of receptacles. He closed the control sample using a filter of thin fabric in a way that would permit only pure air to access the container, that is, without any contaminating element coming from flying insects. In the Esperienze intorno a diverse cose naturali, e particolarmente a quelle che ci son portate dall'Indie [Experiments concerning various natural things, particularly those that come to us from the Indies], published in 1671 and dedicated to Father Athanasius Kircher, who had been criticised in the preceding work for his defence of spontaneous generation, Redi intensified his attack on the unreliability of Jesuit experimental science. In 1684 Redi completed his biological tetralogy with the publication of the Osservazioni intorno agli animali viventi che si trovano negli animali viventi [Observations concerning live animals found in live animals] [fig.4], a treatise on the study of parasites and on comparative anatomy. This was completed with a second section fated never to see the light. In the field of medicine Redi made himself a representative of a reform of the therapy which recommended the prescription of simple remedies, which according to the rules of Hippocratic humourism, should serve to cleanse the organism of the superfluous impurities. Furthermore Redi played a decisive role in identifying the aetiology of scabies studied by Giovan Cosimo Bonomo (1666-1696) and Giacinto Cestoni (1637-1718), showing that infection depended on the attack of the microscopical mite that reproduced through eggs deposited under the skin. Redi was also a fine man of letters. As a member of the Accademia della Crusca, he was an active participant in the drafting of the third edition of the Vocabolario released in 1691. Amongst his literary works he had great success with the famous dithyramb Bacco in Toscana [Bacchus in Tuscany], published in 1685 with many erudite annotations. From 1670 onwards he also worked diligently on a Vocabolario di alcune voci aretine [Vocabulary of some words from Arezzo].