08 SUMMARY OF CURRENT RESEARCHES RELATING TO 



classes the organism with l'>. vulgare and B. Zen kit, and givea the dis- 

 tinguishing characters. 



Decomposition of Cellulose by Aerobic Organisms.* — Van Itersen 

 Jnr., finds that cellulose can be made to dissolve by the action of 

 denitrifying non-sporing aerobic bacteria if the supply of air is limited. 

 Cellulose may be attacked, also, when the air supply is not limited, by 

 certain widely distributed aerobic non-sporing bacteria, among which is 

 the brown pigmented Bacillus f err ugineus. The destruction is especially 

 strong in symbiosis with a yellow micrococcus, which is itself inert. He 

 finds that the destruction of cellulose by moulds is due to an enzyme, to 

 which he gives the name of " cellulase." He considers that one of the 

 origins of the colour of humus is the pigment formed from cellulose by 

 bacteria and moulds. 



Bacterium that obtains its Carbon Food from the Air.f— M. W. 

 Beijerinck and A. van Delden describe an organism which they have 

 named Bacillus Oligocarbophilus ; it obtains its carbon food from certain 

 as yet undetermined carbon compounds of the air. Cultures on solid 

 media and nutrient solutions containing soluble organic substances have 

 failed, whereas pure cultures can readily be obtained on media not con- 

 taining soluble carbon compounds. It was isolated by them from garden 

 soil, inoculated in an alkaline mineral fluid medium, after 2—3 weeks 

 incubation at 23-25° C. ; it appeared as a white or slightly rose-coloured 

 dry film, macroscopically resembling Mycoderma ; it consists of thin, 

 short rods, • 5-1 jx long; it grows slightly or not at all on ordinary 

 media ; it grows well on silica plates ; it does not nitrify. 



Variations in the Colours of Moulds and Bacteria4— T. Milbum 

 finds that the colours of the conidia of Hypocrea rufa and Hypocrea 

 gelatinosa depend on the reaction of the medium ; with an acid reaction 

 green spores are produced, yellow spores being formed on an alkaline 

 medium. He finds that a well nourished mycelium has no fructification 

 in the dark, but by an addition of excess of acid, or with a less nourish- 

 ing medium, the formation of conidia commences. Aspergillus niger 

 forms, besides the well known black colouring matter, a more or less 

 abundant yellow pigment, which the author has also observed in the 

 black spores ; this yellow colour is very sensitive to light, and becomes 

 grey and black after exposure for a few hours. Bacillus ruber balticus 

 also has its pigment production influenced by the reaction of the 

 medium, producing a violet coloration with an acid medium, and an 

 orange-red colour when the medium is alkaline. 



Bacillus helixoides, a bacillus that forms Colonies with Snail- 

 like Movements.§ — T. Muto (Tokio) isolated this organism from his own 

 saliva. Two forms of the bacillus occur in the same colony. Those 

 at the peripheral moving parts of the colony are oval truncated rods, 

 2-4-5 fx long and about m G4 jx broad, existing singly or two or three 



♦ K. Akad. Wetenscbappen, v. (1903) pp. G85-703. 



t Tom. cit.. pp. 398-413. 



% Centralbl. Bakt., l te Abt. Orig., xiii. (1904) pp. 257-75. ; 



§ Op. cit., l ,e Abt, Orig,.. xxxvii. (1904) pp. 321-5. 



