SAPROPHYTES 



397 



'these days since the perfection of the microscope which has 

 enabled men to learn something of this teeming invisible world 

 of life which touches us on every hand. 



451. Development of the Science of Bacteriology. The 

 first authentic report which we have of bacteria having been 

 seen by man was in 1683. ANTHONY VAN LEEUWENHOEK, a 

 Dutch linen weaver, who spent his leisure time in grinding 

 lenses and in using them to study various materials, was the 



FIG. 269. Louis Pasteur. 



FIG. 270. Robert Koch. 



first man to see and to describe these wonderful little living 

 creatures which you are soon to have the privilege of seeing. 

 In a letter to the Royal Society of London, he said: "I saw 

 with wonder that my material contained many tiny animals 

 which moved about in a most amusing fashion." Are you 

 going to see these organisms for the first time "with wonder," 

 or are you going to consider it a commonplace experience just 

 as we do many wonderful things these days? Very little 

 progress was made in the study of bacteria for nearly two cen- 

 turies after Leeuwenhoek's discovery. It was not until the 



