PREFACE. vii 



that Bacteria are killed by a temperature of i4OF. 

 Yet similar organisms will constantly appear and rapidly 

 multiply within closed flasks containing organic fluids, 

 although the flasks and their contents have been pre- 

 viously exposed for some time to a temperature of 

 2i2F. The latter fact has been admitted by almost 

 all experimenters including even Spallanzani and 

 Pasteur and the inference from it must be quite 

 obvious to those who accept this or any lower tem- 

 perature as the thermal limit of organic life. In experi- 

 ments yielding positive results, they would have to 

 admit that the progenitors of the new, and more or less 

 rapidly multiplying brood must have been evolved de 

 novo within the previously superheated flasks. So that, 

 even if nothing more could be said, the positive results 

 which can almost invariably be obtained in experiments 

 conducted with this temperature, should suffice, in the 

 present state of science, to show that living matter may 

 arise de novo more especially when such a conclusion is 

 also supported by the utter break-down of the opposing 

 Panspermic hypothesis. But much stronger evidence can 

 be adduced ; since numerous similarly successful results 

 have been obtained by Pasteur himself, by Pouchet, 

 Mantegazza, Wyman, Cantoni, Oehl, and others 

 although the closed flasks and their contents had been 

 subjected to the influence of still more destructive tem- 

 peratures, ranging from 2I3F to rather over 300?. 

 Several of such experiments are now recorded for the 

 first time ; and their results cannot be reasonably ex- 

 plained except on the supposition that the living things 

 obtained from the closed flasks had been developed 

 from newly-evolved living matter. 



