4 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



they were restricted, like Aristotle, to the notion 

 of a sort of spontaneous hatching of organic beings 

 born in the mud without the aid of parents. 



The Middle Ages retained the ideas of Aristotle, 

 and almost unanimously adopted the theories of 

 the spontaneous generation of fossils or petrifac- 

 tions under varying formulas, such as plastic force, 

 petrifying force, action of the stars, freaks of nature, 

 mineral concretions, carved stones, seminal vapours, 

 and many other analogous theories. These ideas 

 continued to reign almost without opposition till 

 the end of the sixteenth century, notwithstanding 

 the efforts of a few master minds such as Leonardo 

 da Vinci, Fracastoro, and Bernard Palissy to 

 attribute petrified shells and the teeth of fishes, or 

 glossopetrce, to animals who had lived in the sea 

 at the very place where they were actually observed. 

 The seventeenth century saw little by little the 

 antiquated theories of plastic force and of carved 

 stones disappear, and the animal or vegetable origin 

 of fossil remains was definitely established. Un- 

 fortunately the progress of palaeontology was to be 

 retarded for a long space of time by the rise and the 

 success of the diluvian theories, which attributed 

 the dispersion of fossils to the universal deluge, and 

 endeavoured to adapt all these facts to the Mosaic 

 records. Such, for instance, was the case with the 

 famous " man, eye-witness to the Deluge," de- 

 scribed at (Eningen by Jacques Scheuchzer, whose 

 skeleton, now in the museum at Haarlem, is that 

 of a gigantic salamander. 



Yet there were, among these partizans of the 

 Flood, a few men of worth, whose principal merit, 



