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 was 
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 Buffon, the great French nat- 
uralist, who had a theory of organic molecules that he wished 
to sustain. Needham (1713-1784), 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 Needham’s 
first experiments were published in 1748. These experiments 
