CLASSIFICATION AND TAXONOMY OF THE 

 BACTERIA AND BLUEGREEN ALGAE 



By C. B. VAN NIEL 



Hopkins Marine Station of Stanford University 

 Pacific Grove, California 



Introduction 



The early ISSO's as a starting point for the examination of the development of taxo- 

 nomic theory are appropriate not only because of the centenary aspect of the Edinburgh 

 meeting of the British Association but also because they have an intrinsic importance 

 as the culminating point of pre-Darwinian taxonomy, when the natural system had 

 triumphed completely over the Linnean. — Gilmour, 1951, p. 400. 



It might be suggested that a few simple changes in the quotation above, such 

 as the substitution of "California Academy of Sciences" for "Edinburgh meet- 

 ing," would render it applicable to the present chapter. This, however, is far from 

 true. The fact is that a century ago there did not exist even a rudimentary 

 taxonomic theory for the bacteria. And it is highly questionable whether at 

 present we have advanced much beyond the equivalent of a Linnean system. 

 Nevertheless, advances there have been, though hardly in the sense meant by 

 Professor Gilmour. Rather have they been concerned with a clearer appreciation 

 of the problems inherent in the classification and taxonomy of the bacteria and 

 bluegreen algae. 



Tlie following essay is intended as a sketch of the main trends of these devel- 

 opments. It does not contain a detailed description and discussion of the various 

 systems of classification of these organisms that have been proposed in the course 

 of the past century. Information of this sort can be found in various text- and 

 handbooks; Migula's System der Bakterien (1897-1900) and his contribution to 

 Lafar's Handhuch (1904—1907), Buchanan's General Systematic Bacteriology 

 (1925), and Bergey's Manual of Determinative Bacteriology (6th ed., 1948) 

 trace them satisfactorily for the bacteria, and Geitler's extensive treatise on the 

 bluegreen algae (1932) comes close to performing this task for the latter group. 



The Natural Affinities of Bacteria and Bluegreen Algae 



Quoi qu'il en soit, les Schizomycetes ne sont point une classe. Une classe de quoi? 

 ai-je demande au Comite International de Nomenclature a New York en 1939; et aucun 

 des nombreux delegues representant le monde bacteriologiste n'a pu repondre. C'est au 

 moins un embranchement, mais un embranchement autonome, intermediaire entre les 

 regnes animal et vegetal et nettement separ^ d'eux. Pourquoi ne pas avoir le courage 

 de dire: le Regne Bact^rien? — Pr6vot, 1940, p. 10. 



Although first seen and described nearly three hundred years ago by Antonie 

 van Leeuwenhoek, bacteria could not be adequately studied, for lack of an appro- 



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