82 APHORISMS AND REFLECTIONS 



men great in all departments of human activity, 

 which was to intellectual Europe, in the sixteenth 

 and seventeenth centuries, what Germany is in the 

 nineteenth. It was in Italy, and from Italian 

 teachers, that Harvey received the most important 

 part of his scientific education. And it was a student 

 trained in the same schools, Francesco Redi a man 

 of the widest knowledge and most versatile abilities, 

 distinguished alike as scholar, poet, physician and, 

 naturalist who, just two hundred and two years ago, 1 

 published his " Esperienze intorno alia Generazione 

 degl' Insetti," and gave to the world the idea, the 

 growth of which it is my purpose to trace. Redi's 

 book went through five editions in twenty years ; 

 and the extreme simplicity of his experiments, and the 

 clearness of his arguments, gained for his views and 

 for their consequences, almost universal acceptance. 



Redi did not trouble himself much with specu- 

 lative considerations, but attacked particular cases 

 of what was supposed to be "spontaneous genera- 

 tion" experimentally. Here are dead animals, or 

 pieces of meat, says he ; I expose them to the air in 

 hot weather, and in a few days they swarm with 

 maggots. You tell me that these are generated 

 in the dead flesh ; but if I put similar bodies, while 

 quite fresh, into a jar, and tie some fine gauze over 

 the top of the jar, not a maggot makes its appearance, 

 while the dead substances, nevertheless, putrefy just 

 in the same way as before. It is obvious, therefore, 

 that the maggots are not generated by the corruption 

 of the meat ; and that the cause of their formation 

 must be a something which is kept away by gauze. 

 But gauze will not keep away aeriform bodies, or 

 fluids. This something must therefore, exist 

 in the form of solid particles too big to get 

 through the gauze. Nor is one long left in doubt 

 what these solid particles are ; for the blow-flies, 

 attracted by the odour of the meat, swarm round the 

 vessel, and, urged by a powerful but in this case 



1 These words were written in 1870. 



