and the adhesion of the amniotic fluid with the embryo. Liceti was thus the first to recognize that fetal diseases could lead to the malformation of offspring. Liceti dealt with the question of spontaneous generation in his 1628 work De spontaneo viventium ortu libri quatuor, in which he argued that life could be generated from decomposing plant or animal material in which part of the vegetative or sensitive soul remained. In 1630, he published a follow-up work (De anima subiecto corpori nil tribuente, deque seminis vita et efficientia primaria in constitutione foetus) which answered the objections of some of his critics. Medicine Liceti published a collection of examples of long-term fasting in 1612, De his, qui diu vivunt sine alimento. His intention was to argue that humans could live a long time with little or no food; this thesis was attacked by critics (in particular the Portuguese doctor and professor at Pisa, S. Rodriguez de Castro) and so Liceti published two responses, De feriis altricis animaenemeseticae disputationes in 1631 and Athos perfossus, sive Rudens eruditus in 1636. Other medical works include Mulctra, sive De duplici calore corporum naturalium (1634) and Pyronarcha, sive De fulminum natura deque febrium origine (1636), in which he held that a headache is the microcosmic equivalent of the macrocosmic phenomenon of lightning. Liceti further discussed the relationship between the microcosm of the human body and the macrocosm of the universe in his 1635 work De mundi et hominis analogia. Astronomy In his astronomical works, Liceti attempted to defend Aristotelian cosmology and geocentrism against the new ideas of heliocentrism proposed by Galileo and his followers. With the appearance of the famous comets of 1618 (which later gave rise to Galileo's work The Assayer), Liceti published a series of works arguing the Aristotelian view that comets occurred in the sphere of the upper heavens. These works included De novis astris, et cometis libri sex (1623), Controversiae de cometarum quiete, loco boreali sine occasu, parallaxi Aristotelea, sede caelesti, et exacta theoria peripatetica (1625), Ad ingenuum lectorem scholium Camelo Bulla (published as an appendix to his 1627 work De intellectu agente), De regulari motu minimaque parallaxi cometarum coelestium disputationes (1640), and De Terra unico centro motus singularum caeli particularum disputationes (also 1640). Liceti used these studies primarily to attack the views of G. C. Gloriosi (who had succeeded Galileo as chair of mathematics at the University of Padua) and Scipione