ORIGINATION OF LIVING BEINGS. 77 



fectly pure atmosphere of the same constituents as 

 the external air. Of course, he expected he would 

 get no infusorial animalcules at all in that infusion; 

 hut, to his great dismay and discomfiture, he found he 

 almost always did get them. 



Furthermore, it has beeu found that experiments 

 made in the manner described above answer well with 

 most infusions; but that if you fill the vessel with 

 boiled milk, and then stop the neck with cotton-wool, 

 you will have infusoria. So that you see there were two 

 experiments that brought you to one kind of conclusion, 

 and three to another; which was a most unsatisfactory 

 state of things to arrive at iu a scientific inquiry. 



Some few years after this, the question began to be 

 very hotly discussed in France. There was M. Pouchet, 

 a professor at Rouen, a very learned man, but certainly 

 not a very rigid experimentalist. He published a 

 number of experiments of his own, some of which 

 were very ingenious, to show that if you went to 

 work in a proper way, there was a truth iu the doc- 

 trine of spontaneous generation. Well, it was one of 

 the most fortunate things in the world that M. Pouchet 

 took up this question, because it induced a distinguished 

 French chemist, M. Pasteur, to take up the question 

 on the other side; and he has certainly worked it out 

 in the most perfect manner. I am glad to say, too, 

 that he has published his researches in time to enable 

 me to give you an account of them. He verified all 

 the experiments which I have just mentioned to you — 

 and then finding those extraordinary anomalies, as in 

 the case of the mercury bath and the milk, he set 



