BIOGRAPHICAL MEMORANDA 



THE CLASSIFICATION OF MICRO-ORGANISMS 



In the inaugural address Kluyver had also stressed the need for an 

 intensive study of micro-organisms in various directions as a prelimin- 

 ary to developing a more satisfactory system of classification than 

 those in use at the time. 'It is well known', he had asserted, 'that even 

 to-day there exists an exasperating confusion in the area of the clas- 

 sification of the Schizomycetes\ Although the confusion was all too 

 evident from the mere fact that several conflicting and uncoordinated 

 systems were in use side by side, it is doubtful whether Kluyver could 

 have indicated in what respects these systems were defective, or how 

 they could be improved. For it must be realized that a good system- 

 atist must above all be thoroughly familiar with the material to be 

 classified, and this requires an extensive first-hand knowledge and ex- 

 perience such as Kluyver certainly did not yet possess. But through 

 the isolation of numerous pure cultures of diverse micro-organisms 

 and the study of their characteristics in his laboratory this deficiency 

 was gradually repaired. And together with his amazing memory and 

 acute sense of order, the experience gained soon helped him to acquire 

 the background necessary for making constructive proposals. 



The chief reason for the confused state of bacterial classification 

 was that bacteriologists with divergent aims and fields of interest had 

 not been able to agree on what properties should constitute acceptable 

 criteria for the segregation of taxonomic categories. As is only natural, 

 each one had brought his own experience and preferences to bear on 

 the problem. But these were often so different that several independent 

 approaches had been advocated, each one supported by one or more 

 specialists, and leading to several almost 'private' systems. 



Differentiation on the basis of morphology had long ago been used 

 by Ferdinand Colin as a means of classifying the bacteria known to 

 him in a few 'form genera'. In due course some additional morpholog- 

 ical features, such as flagellation, spore formation, and staining prop- 

 erties, had permitted a much needed expansion of the number of 

 these entities. Nevertheless, it soon became clear that the genera com- 

 prised types whose further differentiation was desirable, and this could 

 be accomplished only on the basis of non-morphological criteria. 

 Hence ecology, pathogenicity, and specific biochemical and serol- 

 ogical properties had been introduced as additional aids in distin- 



138 



