THE EXAMINATION OF MILK 419 



organisms have found their way into the milk through the 

 dust. This explanation is not inconsistent with the fact 

 that the trouble of ropy milk has been known to disappear 

 on the substitution of a good for a bad fodder. The recog- 

 nition of ropy milk can be readily made by taking a few 

 drops between the fingers, when it will be found capable of 

 being drawn out into threads. Amongst the organisms 

 producing stringiness in milk, the following are perhaps 

 the most important : 



Bacillus lactis pituitosi. — This organism was isolated by 

 Loffler, who describes it as a stout, slightly curved rodlet, 

 which does not liquefy gelatine. 



Bacillus lactis viscosus. — This organism, which renders 

 milk very stringy, and is known as the viscid-milk bacillus, 

 was first isolated by Adametz. It is a very short rodlet, 

 aerobic, and does not liquefy gelatine. At the ordinary 

 room temperature the milk does not become markedly 

 stringy for some time. 



Streptococcus Hollandicus. — This organism of stringy 

 milk is used in Holland in the manufacture of Edam cheese. 

 The . organism is a coccus which occurs in the form of 

 chains. It does not liquefy gelatine ; it renders milk stringy 

 within twelve to fifteen hours at a temperature of 77° C, 

 the milk becoming sour at the same time. 



Soapy Milk. — Milk which first appears to be normal often 

 acquires a disagreeable soapy taste in from twelve to twenty- 

 four hours. Soapy milk may be produced by the Bacillus 

 lactis saponacei of Weigmann and Ziron {Centralbl. f. 

 Bald., XV., p. 464). It does not coagulate milk, but makes 

 it slimy and slightly ropy, with a faint soapy taste. It 

 grows best at 10° C. Weigmann has also discovered this 

 organism in the straw used as litter, from which it appears 

 that the milk becomes infected when the litter is changed 

 at milking-time. 



27—2 



