SPONTANEOUS GKNEEATION. 279 



buzzing round the meat and frequently alighting on it. 

 The maggots, he thought, might be the half-developed 

 progeny of these flies. 



The inductive guess precedes experiment, by which, 

 however, it must be finally tested. Eedi knew this, and 

 acted accordingly. Placing fresh meat in a jar and 

 covering the mouth with paper, he found that, though 

 the meat putrefied in the ordinary way, it never bred 

 maggots, while the same meat placed in open jars soon 

 swarmed with these organisms. For the paper cover 

 he then substituted fine gauze, through which the 

 odour of the meat could rise. Over it the flies buzzed, 

 and on it they laid their eggs, but, the meshes being too 

 small to permit the eggs to fall through, no maggots 

 were generated in the meat. They were, on the con- 

 trary, hatched upon the gauze. By a series of such 

 experiments Eedi destroyed the belief in the sponta- 

 neous generation of maggots in meat, and with it 

 doubtless many related beliefs. The combat was con- 

 tinued by Vallisneri, Schwammerdam, and Eeaumur, 

 who succeeded in banishing the notion of spontaneous 

 generation from the scientific minds of their day. 

 Indeed, as regards such complex organisms as those 

 which formed the subject of their researches, the notion 

 was banished for ever. 



But the discovery and improvement of the micro- 

 scope, though giving a death-blow to much that 

 had been previously written and believed regarding 

 spontaneous generation, brought also into view a world 

 of life formed of individuals so minute — so close as it 

 seemed to the ultimate particles of matter — as to sug- 

 gest an easy passage from atoms to organisms. Animal 

 and vegetable infusions exposed to the air were found 

 clouded and crowded with creatiures far beyond the 

 reach of unaided vision, but perfectly visible to an eye 



