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To the typical slime producing species belongs the microbe of the 

 long whej {Lactococcus hollandiae), which particularly before the 

 introduction of pure cultures in the dairy industries, played an 

 important part in the fight against cheese detects in North-Holland, 

 and is still here and there practically used to that end. 



Further I have found thai the popular food known in Norway 

 as "tjaette molken", a sample of which I owe to the kindness of 

 Mr. Pennine of Rotterdam, consists of milk, in which the long whey 

 microbe, or at least a nearly allied form, secretes acid and slime. 



Other materials in which these and allied microbes occur, were. 

 till now unknown, evidently because of the uncertainty about 

 culture conditions and the lack of a good accumulation method. 

 Taking the idea "species" in the broad sense, I think there is no 

 objection as to bringing the group of forms, found in the manner 

 described below, to the species just mentioned. 



Starting from the following properties, the most characteristic for 

 the microbes of the slimy lactic acid fermentation: 



1 st . The optimum temperature for their growth is at 20° or lower, 



2 nd . they can only compete in anaerobic cultures with the other 

 microbes, and 



3 rd . the medium must consist of substances containing peptones 

 as nitrogen and carbon hydrates as carbon source, I succeeded in 

 finding a method giving rise to their accumulation. 



It is true that 1 only examined a single material in this way, the 

 common baker's yeast, but the investigation of the soil of fermenting 

 or fermented substances, in short of materials of most varying de- 

 scription may be done in a corresponding way. 



The experiment is arranged as follows. 



Into a 30 c.c. closed bottle, fdled with maltextract, to which is 

 added ' / 8 °/ of peptone siccum and which contains c.a. 10% extract, 

 a little pressed yeast is introduced, fur instance ' ., gram. Placed at 

 a temperature of 18 to 20° 0. a (poet fermentation sets in, which is 

 allowed to continue 24 .to 72 hours, whereby, because of the absence 

 of air the yeast hardly grows, but the various lactic acid ferments 

 reproduce quickly. Other microbes do not develop. Not seldom in 

 this first culture have the contents of the tlask already become 

 somewhat slimy. 



Whether this be the case or not, a not too small quantity from 

 it is transplanted into a bottle quite filled with boiled, air-free milk, 

 for instance 7 3 c.c. into 30 c.c. of milk. At the same low or a some- 

 what higher temperature only a flora of lactic acid ferments can 

 develop, and if the slime-forming species is present, it is the most 



