ROPY MILK. 291 



136. Ropy Milk. The so-called "ropy" milk is milk which has 

 been converted by the fermentation of certain kinds of bacteria into 

 a peculiar condition. It is of a thickish uniform leathery consistency, 

 and runs, when poured from a spoon, in threads of considerable 

 length, which often draw out to the fineness of hairs. It tastes 

 slightly sour, contains its casein in the form of an extremely fine 

 suspended flocculent powder, and, at a comparatively low tempera- 

 ture, may be kept for months in an almost unchanged condition. 

 It is much liked in Norway and in Northern Sweden and Finland, 

 where it forms an article of commerce. The author has seen such 

 ropy milk at the market at Helsingfors, whither it had been brought 

 in little wooden barrels by the peasants living in the neighbouring 

 districts. The method in which lange milch is prepared in the 

 above-mentioned countries we do not exactly know. It is also 

 unknown whether its condition is due to zoogloea-building bacteria, 

 or bacteria which convert the milk-serum into a thready condition 

 through change of the milk-sugar. The author is not aware of any 

 accurate analyses that have as yet been made of ropy milk. 



Lange milch is not used in Germany as an article of food. It is, 

 however, occasionally known as an undesirable disorder in milk. As such 

 disorders are not altogether uncommon, and, as the author knows by 

 experience, often occur in well-conducted dairies, it follows that the 

 bacteria which induce this thread-like consistency in milk or cream must 

 be of pretty wide occurrence. It has been asserted that ropy milk may 

 be prepared by the help of a plant, Pinguicula, in those countries in which 

 it is regularly made. The author doubts this, however, since in repeated 

 experiments with the Pinguicula vulgaris and the Pinguicula alpina he has 

 never succeeded in producing this thready consistency in milk. If, how- 

 ever, it does take place, he believes it must be attributed to the agency of 

 bacteria, which change the milk in this way, and which find in the above- 

 mentioned plant a congenial nourishing soil, and hence are often found 

 in it. 



137. Milk-sugar. Of all the bye-products of milk, milk-sugar is 

 by far the most important. Milk-sugar, the properties of which 

 have been more particularly described in 1 7, can never, on account 

 of its hardness and its only slightly sweetish taste, supplant 

 cane- or beetroot-sugar for ordinary domestic "purposes, but for 

 almost all technical uses to which sugar is put, it is as suitable as 

 the other two kinds of sugar. Its use, however, is handicapped by 



