LECTURE XL. 

 SPONTANEOUS GENERATION. 



Assumed by early writers. Omne vivum ex ovo. 

 Omne vivum ex vivo. Discovery of infusoria. Ehren- 

 berg. Assumption of their spontaneous generation, 

 bridging the gape between living and non-living. 



Work of Bastian on breeding infusoria in the in- 

 terest of materialistic philosophy. 



Work of Tyndall on cleaning tubes for optical ex- 

 periments. 



Work of Lister in antiseptic surgery. 



Work of Pasteur on diseases of vines. 



Work of Pasteur and others on fermentation. 



Work of Jenner on smallpox. 



Work of Koch on tuberculosis. 



Experiments of Tyndall on floating matter in the 

 air shows that germs of infusoria and bacteria are 

 everywhere present, and that all these men were deal- 

 ing with the same phenomena, the unsuspected germs 

 of unicellular animals and plants, not easily destroyed. 

 Germ theory of disease. Fermentation as " life with- 

 out air." 



No evidence that spontaneous generation now oc- 

 curs. No possibility of recognizing it, should it do so. 



