INTRODUCTION 9 



ods; that he strictly belongs to the Galilean school, as 

 many writers state, is hardly exact. He was not, nor 

 were most pure biologists, led into the acceptance of an 

 entirely physico-mechanical interpretation of Nature, as 

 were Borelli, Descartes, and others, who carried the new 

 teaching to the extreme, and ended in assuming that the 

 human body is a machine, moved (Aristotle to the res- 

 cue!) by the pneuma, or spiritus. 



Galileo had proved the falsity of Aristotle's theory of 

 motion, but another doctrine of his lay open to discus- 

 sion, namely: spontaneous generation, an ancient and 

 persistent popular belief, which the father of biology had 

 accepted, being unable to find any other origin for the 

 lower animals. Paracelsus was an extreme exponent of 

 the theory, attempting, it was said, to re-create human 

 life. His reported experiments in this line excited the 

 indignation of our orthodox author, who saw in them 

 an attack on the mystery of Faith. Harvey, in spite of 

 "" omne vivum ex ovo," did not contradict the Greek 

 philosopher, neither did Cesalpino of Arezzo, the discov- 

 erer, of the circulation of blood in the lungs. Giuseppe 

 Aromatari of Assisi was the first to publish his disbe- 

 lief in the time-honored tradition. In his treatise, *' De 

 Rabia Contagiosa" (Venice, 1625), writing on the gen- 

 eration of plants, he insists that they arise from the seed, 

 and that likewise all animals are born from the t%g. 

 Redi, however, was the first to prove this truth by ex- 

 periments, that have been compared to those of Tyndall 

 and Pasteur two hundred years later. Not content with 

 merely recording what he perceived, he created new 

 conditions in which the objects examined presented new 

 aspects, reaching in this way a different viewpoint from 

 that of the ordinary observer. Redi also possessed a 



