216 ROPINESS IN MILK, WINE, BEER, ETC. 



turns milk ropy within five hours at 22 C. The optimum temperature of 

 development is two degrees lower, and the microbe is destroyed by an exposure 

 of two minutes to boiling heat. It has frequently been found in the district of 

 Berne, and often causes considerable damage. 



Simultaneously with this last-named organism, a third microbe, also endowed 

 with the faculty of turning milk ropy, was introduced by Guillebeau under the 

 name of Bacterium Hessii. This species, which appears in the form of actively 

 motile rods, 3-5 p. long and 1.2 p. broad, is less injurious than the one just 

 described, since the ropiness it produces in milk disappears directly acidification 

 sets in. 



The substantive cause of the mucinous condition may be of three kinds. 

 Either it is attributable to the swelling of the membrane of the bacteria in 

 question as is apparently the case in those already alluded to as capsule bacilli, 

 e.g. Actinobacter, B. lactis viscosus, and also, according to the researches of 

 W. VIGNAL (I.), with B. mesentericus vulyatiis or, secondly, the milk-sugar is 

 converted into a mucinous substance. This was asserted to be the case by 

 Storch for two species of bacteria discovered by him, and was proved by G. 

 LEICHMANN (III.) for a bacillus isolated from ropy inilk. This latter organism 

 acts on lactose, cane-sugar, maltose, galactose, levulose, and dextrose (but not 

 on mannite, arabin, or starch) in such a manner that mucus and lactic acid are 

 formed, together with a small quantity of ethyl alcohol. In the third place, the 

 ropy substance can also be produced from the casein of the milk. According to 

 H. WEIGMANN, this latter cause operates in the formation of the milk products 

 known as 



163. Ropy Whey (Lang-e Wei) and Thick Milk (TsettemaBlk). 



The Swiss dairymen discard ropy milk for cheese -making, being afraid of its 

 ca.using " nests," i.e. places within the cheese where the ripening proceeds 

 irregularly. They therefore devote particular attention to fumigating the stalls 

 out with burning sulphur, scouring the milk vessels with soda solution, &c., in 

 order to eradicate the evil as quickly as possible. 



On the other hand, the Dutch look on the bright side of this evil, and even 

 derive benefit from it, the most palatable production of the Netherlands, viz., 

 Edam cheese, being prepared with the aid of ropy whey (Dutch, Wei). The 

 first observations on and experiments with this ropy whey were made in the 

 " fifties" by a farmer (name unknown) of Assendelft, in Holland, but it did not 

 come into general use iu the manufacture of Edam cheese until 1887, when 

 Boekel recommended it most emphatically. 



WEIGMANN (VII.) examined such whey, and found in it lai-ge quantities of 

 a fission fungus, which is mostly arranged in pairs, but frequently also in chains, 

 and bears the name of Streptococcus hollandicus. Sterile milk inoculated with 

 this organism becomes ropy and sour in twelve to fifteen hours at 25 C. 



The same coccus was also found by Weigmann in the commercial products 

 known as Tcett&mcdk or Tcetmcdk (thick milk) in Norway, and Filmjolk (stringy 

 milk) in Finland and Sweden. This strongly sour, ropy, thick mass, the casein 

 of which is in the condition of fine flakes, is a highly prized article of nourish- 

 ment among the Scandinavian races, and is artificially prepared from normal 

 milk by either rubbing the interior of the milk-pails over with butter-wort 

 (Pinguiculavulgaris), called in Norway Tcettegrces, or by feeding this plant to the 

 milch-cows. The leaves are found to be infested with a fission fungus which 

 turns milk ropy, and is presumably identical with the above-named strepto- 

 coccus. As already remarked, the occurrence of ropiness in milk is usually 

 accompanied by acidification, whereby the development of numerous other 



