1 80 FERMENTA TION IN MILK 



js^ (6.) Ropy OP Viscous Milk 



This is a condition of milk produced by certain micro-organisms, 

 some of which have, however, an economic value in the preparation 

 of certain milk products, and can therefore, scarcely be looked upon 

 as " disease-producing." Nevertheless., this condition has been 

 traced apparently to garget in the cow.\ Under conditions favour- 

 able to the development of the organisms, the ropiness appears 

 within from twelve to twenty-four hours after milking, and is 

 so pronounced that the milk can be drawn out in long threads 

 or strings. , This is a not uncommon condition of milk in Swit- 

 zerland, where it is considered specially noxious, but in Holland, 

 since the year 1887, it has been produced by design in the making 

 of Edam cheese. Such cheese ripens quickly and uniformly. 



It is to Schmidt-Muhlheim (1882) that we are indebted for the 

 first investigation of this disease of milk from a bacteriological 

 point of view,^ although the question had been studied chemically 

 by Girardin as far back as the year 1847, ^"d later by Lister 

 (1878)^ who was the first artificially to infect milk with the disease. 



With the study of the question by Duclaux, however, began 

 the first serious attempt to differentiate the various organisms 

 acting as causation of the disease, and these may now be classified 

 as follows : — 



I. Bacillus actinobacter {Actinobacter polymorphiis) of Duclaux. 

 — A long, thin, non-sporing, facultative anaerobic bacillus of 2 to 

 3 mm. in length, isolated or appearing in pairs, a most interest- 

 ing feature being the presence around each organism of an ovoid 

 or rounded gelatinous capsule of from 5 to 6 mm. in length, 

 two bacilli, united end on end, at times being enclosed in the one 

 capsule. In old cultures a shortened form of the rods is observed. 

 The organism grows freely, at ordinary temperature, on almost all 

 the usual laboratory media, showing however a somewhat extra- 

 ordinary variety of morphological characteristics, according to the 

 medium employed, a character clearly recognised by Duclaux, when 

 he applied to it the nomenclature oi Actinobacter polyjuorpJius. 



In bouillon there is a characteristic formation of white flocculi, 

 which on microscopic examination are seen to be made up of 



^ The organism, supposed by Schmidt-Miihlheim to be the active agent of 

 this disease, was described by him as "an apparently motile micrococcus of 

 I mm. in diameter, isolated or appearing sometimes in chains." No pure 

 culture, however, of this organism seems to have been obtained by him. 



2 Quarterly Journal of Microscopical Science., Oct. 1878, p. 391. 



