14 Microbes and You 



beaver, and elk, wood from many types of trees, etc. He was 

 amazed to discover that the sperms of an ox and of a mouse were 

 much ahke in size. 



It was not until he examined drops of water, however, that 

 Leeuwenhoek began to see amazing creatures— a thousand times 

 smaller than the limits for the human eye. Since the beginning 

 of time these sub-visible creatures had wreaked their havoc, had 

 killed the innocent child as well as the adult rascal; had played 

 important roles in the essential process of decay and putrefaction, 

 in soil fertility, and in fermentations resulting in the production of 

 wine and other beverages. "They stop, they stand still as 'twere 

 upon a point, and then turn themselves round with that swiftness, 

 as we see a top turn round, the circumference they make being 

 no bigger than that of a fine grain of sand," he wrote. It is 

 always a pleasant experience to observe the reaction of students 

 peering through a microscope and viewing for the first time the 

 nervous activity of the strange, new world in a drop of stagnant 

 water. Students are informed that there are such things in 

 existence, but how would a person react were he living back in 

 the seventeenth century looking at this same drop of stagnant 

 water and seeing sub-visible families that no other person had 

 ever seen before? Leeuwenhoek was jubilant! 



As we examine these early records of his observations we find 

 them startlingly accurate. He once wrote that one of his "beasties" 

 was one-thousand times smaller than the eye of a large louse. We 

 have since learned that the eyes of all adult lice are no smaller 

 nor larger than the eyes of sister and brother lice. 



His findings in stagnant water drove him mercilessly on in his 

 observations, and he naturally wondered whether these "animal- 

 cules" arrived on earth in rain water. Samples of rain water were 

 carefully collected in clean containers, and examination of drops 

 of this fluid revealed no organisms. However, after dust and lint 

 had fallen into his container and sufficient time had elapsed, he 

 was able to show that life abounded in his stored liquid. 



While trying to find out what made pepper bite his tongue, he 

 cut the condiment into pieces for easier microscopic examination. 



