THE ORIGIN OF LIFE 105 



the sea, produced worms, which engendered 

 butterflies, and the butterflies, strangest of 

 all, became birds. But it was also from 

 Italy that the first critical experimental 

 observation came : Redi, a poet and physician 

 of that country, clearly demonstrated that 

 larvae were not engendered spontaneously in 

 decomposing meat, by taking the simple 

 precaution of placing the meat in a wide- 

 mouthed bottle and covering the mouth of 

 the bottle with gauze. Flies attracted by the 

 odour, deposited their eggs on the gauze, and 

 Redi showed that it was from these and not by 

 spontaneous generation that the so-called 

 worms arose. Valisneri, another Italian scien- 

 tist, gave a similar demonstration for fruit 

 grubs, and thus the basis of our knowledge of 

 the interesting metamorphosis of insects was 

 laid. Later on, that great physiologist, the 

 Abbe Spallanzani, after the advent of the 

 microscope, really quite clearly proved the 

 fallacy of spontaneous generation by experi- 

 ments as decisive as those of Pasteur a century 

 later. But the age was not receptive, nor was 

 the ground then prepared for the world to 

 understand the importance of the discovery, or 

 take that lead towards the knowledge of the 

 causes of disease which in the hands of 

 Pasteur resulted from his discovery. 



