S4 Microbes and You 



It seems important to review the thinking that preceded this 

 final classification whereby bacteria are catalogued under the 

 Thollopliijta. You may recall that Antony van Leeuwenhoek, the 

 first person to leave written descriptions of bacteria, referred to 

 these organisms as "animalcules," since their active motility sug- 

 gested small, darting animals. Carl von Linne (1707-1778), the 

 Swedish botanist who is better known as Linnaeus, couldn't decide 

 where to place bacteria in his Sijstema Naturae, in which he listed 

 all plants and animals recognized up to that time. However, he 

 finallv did call bacteria animals in the class Vermes and the order 

 Chaos, where they remained until more could be learned about 

 them. The first organized attempt to bring order out of this chaos 

 was in 1774 with the work of Otto F. Miiller (1730-1784), a Dutch 

 naturalist, who placed bacteria among the ciliated protozoa. He 

 included a genus he called Vibrio, a term still in common usage. 

 Felix Dujardin (1801-1860), not knowing whether bacteria were 

 plants or animals, reached a happy solution by naming them 

 Zoophvtes, which means animal-plants. Christian Ehrenberg 

 (1795-1879) published his grouping of organisms in 1839, and he 

 includes four sjenera familiar to modern bacteriologists: Bacterium. 

 SpiriUum, Spirochaeta, and Vibrio. 



As early as 1857 Karl Nageli ( 1817-1891 ) introduced the word 

 Schizomifcetes (fission fungi) and this is the class under which we 

 find bacteria in modern classification schemes. This helped to set 

 the pattern for workers interested in supporting the idea that 

 bacteria belong to the plant kingdom. A great lift was given to 

 this school of thought when Ferdinand Cohn in 1872 published the 

 first systematic classification of bacteria. He pointed out that group- 

 ing these organisms into genera and into species was not only 

 possible, but that it was logical. It was not, however, until Gual- 

 terio Migula at the turn of the twentieth century classified bacteria 

 on the basis of morphology (size, shape, and structure)— especially 

 motility and arrangement of the flagella— that wide acceptance of 

 any scheme was encouraged. The technical difficulties involved 

 in trying to stain flagella soon became onlv too apparent, and Orla- 

 Jensen in 1909 expanded the base for criteria emploved in taxonomy 



