60 PASTEUR 



known that the ancients believed that eels were 

 born from the slime of river banks, and that it 

 did not seem to them impossible that bees 

 should issue from the decomposing entrails of 

 a bull. Without going quite so far back, we 

 find that the great naturalist, Buff on, supported 

 the theory of spontaneous generation; but the 

 first experiments to prove its truth were made 

 by an Irishman, Needham, in the eighteenth 

 century. Enclosing putrefying matter in a ves- 

 sel which he sealed hermetically, and heating 

 the whole apparatus in hot ashes, in order to 

 destroy all living germs, he allowed the vessel 

 to become cold, and after the lapse of several 

 days he found that it contained animalcula. 

 This went to prove that spontaneous genera- 

 tion had taken place. Spallanzani repeated 

 these experiments, and, after heating the closed 

 vessel to a higher degree, observed that no ani- 

 makula afterwards developed. Needham re- 

 joined that by using too high a degree of heat 

 he had killed the vegetative force from which 

 creation proceeded. None of these experiments 



