444 BACTERIOLOGY. 



succeeded as early as 1729 in cultivating many 

 moulds from spore to spore. So far as the 

 smut and rust fungi were concerned, however, 

 origin by heterogenesis seemed still possible 

 till in 1801, Persoon, and in 1853 De Bary 

 solved this question finally. The notion of 

 the spontaneous generation of insects was 

 overthrown by Swammerdam (1669) and Redi 

 (1688), so that the supporters of this doctrine 

 were forced to have recourse to still smaller 

 organisms. Needham believed that he could 

 prove experimentally the spontaneous genera- 

 tion of "infusion animals" and his conclu- 

 sions met with general assent for a time, but 

 Bonnet (1762) and Spallanzani (1769) over- 

 threw his claim so completely that Appert 

 (1809) was able to devise a successful method 

 for the preservation of food materials on the 

 basis of their work. This was the first practi- 

 cal result of the older bacteriology. New op- 

 ponents continued to arise till Franz Schulze 

 (1836), Schwann (1837), Schroeder and v. 

 Dusch (1854-1861), van der Broek (1857) and 

 Pasteur (from 1857 onwards) overthrew by con- 

 clusive evidence every argument for spontane- 

 ous generation, and demonstrated that all mi- 

 crobes arise by legitimate descent out of germs 

 of the same kind. The doctrine of spontane- 

 ous generation became in the hands of Bechamp 



