PASTEUR, KOCH, AND OTHERS 281 



lated into Latin, and were published in miniature, making 

 books not more than four inches high. Huxley says: "The 

 extreme simplicity of his experiments, and the clearness of 

 his arguments, gained for his views and for their conse- 

 quences almost universal acceptance." 



New Form of the Question. — The question of the spon- 

 taneous generation of life was soon to take on a new aspect. 

 Seven years after the experiments of Redi, Leeuwenhoek 

 made known a new world of microscopic organisms — the 

 infusoria — and, as we have seen, he discovered, in 1687, those 

 still minuter forms, the bacteria. Strictly speaking, the 

 bacteria, on account of their extreme minuteness, were lost 

 sight of, but spontaneous generation was evoked to account 

 for the birth of all microscopic organisms, and the question 

 circled mainly around the infusorial animalcula. While the 

 belief in the spontaneous generation of life among forms 

 visible to the unaided eye had been surrendered, nevertheless 

 doubts were entertained as to the origin of microscopic organ- 

 isms, and it was now asserted that here were found the be- 

 ginnings of life — the place where inorganic material ^^as 

 changed through natural agencies into organized beings 

 microscopic in size. 



More than seventy years elapsed before the matter was 

 again subjected to experimental tests. Then Needham, 

 using the method of Redi, began to experiment on the pro- 

 duction of microscopic animalcula. In many of his experi- 

 ments he was associated with Buff on, the great French nat- 

 uralist, who had a theory of organic molecules that he wished 

 to sustain. Needham (i 713-1784), a priest of the Catholic 

 faith, was an Englishman living on the Continent ; he was 

 for many years director of the Academy of Maria Theresa at 

 Brussels. He engaged in scientific investigations in connec- 

 tion with his work of teaching. The results of Xeedham's 

 first experiments were published in 1 748. These experiments 



