BIOGRAPHICAL MEMORANDA 



formation may permit the establishment of subgroups more nearly 

 equivalent to those based on particular anaerobic processes. 



Although the outline of bacterial classification presented in 1936, like 

 any and all other systems that have thus far been proposed, is subject 

 to the criticism that it does not rest on a truly phylogenetic basis [Van 

 Niel 1955], its rational features have had a beneficial influence on 

 systematic bacteriology generally, and many of the genera there delin- 

 eated have gradually been incorporated in the current systems. 



Besides the main outline mentioned above, the contributions to 

 bacterial classification of Kluyver and his associates comprise many 

 publications on problems of a more limited scope. The monographic 

 treatments of the genera Acetobacter [Visser 't Hooft, 1925TI1; Fra- 

 teur, 1950], Protaminobacter [Den Dooren de Jong, 1926TI1, 1927], 

 Propionibacterium [Van Niel, 1928TI1], Pediococcus [Mees, 1934Tb], and 

 Spirillum [Giesberger, 1936Tb] ; of the group of sulphate reducing bac- 

 teria [Baars, 1930Tb], brine bacteria [Hof, 1935Tb], and methane 

 producing bacteria [Schnellen, 1947Tb], all these will long remain 

 amongst the indispensable references to these groups. Giesberger later 

 extended his studies of the spirilla to the reddish-brown members of the 

 genus Rho do spirillum; Kingma Boltjes [1934Tb, 1936] made a careful 

 investigation of the nitrifying bacteria during which he rediscovered 

 Hyphomicrobium vulgare, whose strange life cycle, including the multi- 

 plication by budding, was described in detail; Mayer [1938Tb] and 

 Perquin [1939] made notable contributions to our knowledge of the 

 dextran-producing Betabacterium vermiforme and Streptobacterium dex- 

 tranicum, respectively; and Kaars Sijpesteyn [1948Tb, 1949, 1951] to 

 that of the cellulose-decomposing bacteria in rumen, leading to the 

 establishment of the new genus, Ruminococcus. Here may also be men- 

 tioned the discovery of Pseudomonas beijerinckii [Kluyver and Hof, 1939; 

 Kluyver, Hof and Boezaardt, 1939], characterized by the production 

 of a purple pigment only if the organism is grown in the presence of 

 inositol, which is oxidized to tetra hydroxyquinone, whose calcium 

 and magnesium complexes are responsible for the colour of the cul- 

 tures ; of Ps. aureofaciens [Kluyver, 1 956] ; and of Hydrogenomonas car- 

 boxydovorans [Kistner, 1953, 1954] which can live at the expense of 

 the oxidation of carbon monoxide. The comparative studies of the 

 aerobic nitrogen fixing bacteria of the Azotobacter [Kluyver and Van 

 Reenen, 1933; Kluyver and Van den Bout, 1936] and Beijerinckia 



144 



