ON THE VEGETABLE CHEESE, NATTTO. 



69 



gelatine and producing a greenish fluorescence. It forms 

 white ilocculent masses on potatoes, and on soya beans it 

 forms white colonies. With regard to the micrococci the 

 colonies of the three kinds can be distinguished by their colors : 

 yellow, orange yellow, and white. [) 



The yellow micrococcus belongs to the larger kinds. In 

 gelatine it forms white colonies along the canal. At the head 

 of the canal a concavity is formed. The gelatine is in a small 

 degree liquified. On agar, potatoes, and soya beans, it first 

 forms white colonies that gradually turn yellowish. On soya 

 beans it develops the characteristic smell which is observed 

 with natto itself. In 2 % peptone solution it forms a white 

 deposit. 



The orange yellow micrococcus forms round colonies on 

 gelatine. It has a general resemblance to the former but it does 

 not liquify gelatine at all, and produces on soya beans a dis- 

 agreeable smell. While the former does not spread considerably 

 on potatoes, this one does so forming a slimy cover. 



The white micrococcus has a general resemblance, in regard 

 to growth and development of its colonies, to the last named. 

 With regard to the specific smell of natto, repeated experiments 

 have convinced me that the above mentioned yellow micrococcus 

 is the chief cause, while with regard to the slimy substance 

 which shows an enormous degree of viscidity further experiments 

 have to be carried out ; because the yellow micrococcus is not 

 the cause of this viscidity. 2) 



2, Chemical Investigation. 



As the soya bean is very rich in protein, the various decom- 

 position products of proteids might be expected to be present 

 in this cheese to a certain extent. 6.8 kilos, of the raw cheese 

 were extracted with boiling water, and the aqueous solution 

 precipitated with basic acetate of lead. The filtrate from this 



1) White colonies were far less numerous than the others. 



2) I made also several experiments to observe the degree of resistance to 

 hydrochloric acid, and found that the microbes mentioned remained alive in 2°/ 0 

 peptone solution containing o,n 0 / o HC1, but they were killed when hydrochloric 

 acid was increased to o,ig°/ 0 . 



