Highlights in the History of Microbiology 15 



but when these pieces were still too large to be conveniently placed 

 under his lenses, he decided to soak the pepper in water to facilitate 

 cutting into smaller units. Lo and behold, four days later the 

 pepper water was teeming with life. This might be considered as 

 the first bacteriological medium devised for growing organisms 

 in the laboratory. With his calculating mind he reported to the 

 Royal Society that a single drop of his pepper water contained 

 more than 2,700,000 of these little animals— more than the total 

 population of his native country! This was, after all, a rather 

 startling revelation, and scoffers were in the majority. A few in- 

 dividuals, however, remembered how accurate his previous ob- 

 servations had been, and they tried to get Leeuwenhoek to reveal 

 his technic of manufacturing microscopes. He was a jealous man 

 and refused the request, but he finally did condescend to sub- 

 mit his calculations to show how he had arrived at his conclusions 

 relative to the pepper water populations. 



People might look at some of his instruments, but touch them— 

 never. In his famed letter of October 9, 1676, to the Royal 

 Society he wrote: "My method for seeing the very smallest 

 animalcules and minute eels, I do not impart to others; nor how to 

 see very many animalcules at one time. That I keep for myself 

 alone." 



Barnett Cohen in 1937 offered the following explanation of 

 Leeuwenhoek's success which others at the time could not seem 

 to duplicate. "One can augment the effectiveness of a simple 

 lens by suitably utilizing the inherent optical properties of the 

 spherical drop of fluid containing the objects under observation. 

 The advantages of a water-immersion objective are too well known 

 to require comment, but the added advantage of what amounts 

 to the super-position of a relatively thick meniscus lens (of water) 

 may be worthy of mention. There is apparently no way to prove 

 that Leeuwenhoek did actually employ either of the simple devices 

 set forth above; but certainly, their production was well within 

 the facilities and competence of that clever manipulator." 



It is recorded that the Royal Society instructed two of its 

 members— Robert Hooke and Nehemiah Grew— to build the best. 



