CHAPTER III. 

 THE NATURE OF MATTER 



WE have seen how the progressive improvement of the 

 microscope has tended to simplify the problem of the origin 

 of life. A century ago insects and small worms and crus- 

 taceans (like fleas) were counted among the lowest repre- 

 sentatives of the animal world, and science itself had only 

 just surrendered a belief in their spontaneous generation. 

 Then the microscope began to reveal whole worlds of 

 living things at a far lower level. Scientists still made the 

 mistake at times of taking provisional determinations for 

 final truths. One of the leading microscopists in Europe 

 fifty years ago, Ehrenberg, wrote a work to show that the 

 infusoria he detected in a drop of stagnant water were 

 "perfect organisms." The dim markings his poor micro- 

 scope discovered in them were shaped by his imagination 

 into the outlines of complete organs. Other scientists, 

 such as Joly and Pouchet, Pasteur's great adversaries, 

 claimed that the infusoria were rudimentary enough to be 

 born by spontaneous generation. Both extremes were 

 wrong. But the microscope went on to reveal to us the 

 hundreds of species of minute, structureless beings we 

 described in the last chapter, and so brought us within sight 

 of the frontiers of the inorganic world. 



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