I 



ROPY MILK 183 



a thick, slightly curved rod, growing rapidly at room temperature 

 and not liquefying gelatine. 



According to Fliigge, the rods quickly break up into segments 

 resembling cocci. On gelatine plates the colonies are white, with 

 a brownish hue by transmitted light. They are of from -2 to -5 

 mm. in diameter, radiating from centre, and with sharply defined 

 contours. On agar these colonies are of a dirtyish white colour. 

 On potato the growth is of a greyish-white, dry and somewhat 

 granulated. Milk, infected .with the organism, takes a distinctive 

 odour and becomes sour and slimy, the ropy condition being more 

 marked in the lower strata. 



It is well to observe that although to the above described 

 organisms, the condition known as ropy or viscous milk may under 

 ordinary circumstances be ascribed, there are many other micro- 

 organisms which seem to be endowed with this peculiar property. 

 Amongst these may be cited the Bacillus inesentericus vulgatus 

 of Fliigge — specially studied by W. Vignal ; the Bacillus viscosus 

 I and 2 of Van Laer — isolated from ropy beer, but producing the 

 same effect in milk ; the Bacillus gummosus of Happ and others. 

 To various common milk organisms, such as B. lactis aerogenes, 

 has also been attributed the power of creating slimy milk. 



According to Fliigge, it is questionable whether the slimy 

 condition of milk is not identical with the slimy fermentation of 

 substances containing saccharose, such as the juice of the beet and 

 other ClienopodicuicB, produced by such organisms as Leuconostoc 

 vtesenteroides of Crenkowsky and Van Tieghem, and the Bacillus 

 viscosus saccJiari of Kramer. 



Allusion has already been made to the fact that although in 

 most countries, and especially in Switzerland, this peculiar con- 

 dition of milk is looked upon as one of the greatest pests of the 

 cheese-maker, and special attention is paid to its eradication, 

 immediately it has gained admittance to a dairy, by thoroughly 

 fumigating and cleansing both the byres and the dairy, yet in 

 Holland it is produced by design in the manufacture of Edam 

 cheese, by the introduction into the whey of the micro-organism 

 specially studied by Weigmann, and known as the Streptococcus 

 Hollandicus, which, introduced into sterile milk, causes it to 

 become ropy and sour in twelve to fifteen hours at a temperature 

 of from 25"" to 30'' C. This organism was also observed by 

 Weigmann in the commercial products of Nor%vay and Sweden 

 known as Toetmoelk or Taettamoelk (thick milk) and Filmjdlk 

 (stringy milk), which are prepared by rubbing the interior of the 



