BLUE MILK 171 



by such milk contains, however, only a small quantity of coagulated 

 casein, the bulk consisting of small fragments of decomposed 

 colostrum. As the cells of this latter substance die off a slight 

 degree of acidification ensues, which causes the precipitation of 

 a certain quantity of casein.^ 



5. Diseases of Milk 



A " disease " of milk may be described as the production 

 therein, by the action of a specific micro-organism, of such an 

 organic change as will render it or its resultant products unfit for 

 human alimentary purposes, although in themselves they may have 

 neither poisonous nor pathogenic properties. Some authorities 

 have described these conditions as " milk anomalies." 



The diseases of milk, properly so called, are but few in number 

 and they may be comprised under the following heads, viz. : — 

 I. Blue Milk. 2. Red Milk. 3. Yellow Milk. 4. Bitter Milk. 

 5. Soapy Milk. 6. Viscous, Ropy, or Slimy Milk. 



(i.) Blue Milk 



A disease characterised by blue flecks in the milk either locally 

 on the surface or permeating the whole mass by diffusion, and 

 appearing in from twenty-four to seventy-two hours after milking, 

 according to temperature and climatic conditions. 



The first attempt to investigate the nature of this disease, 

 which frequently takes an epidemic form, appears to have been 

 made by Ehrenberg and Steinhof about the year 1838, but it was 

 not until the year 1841 that Fuchs, working in their footsteps, 

 clearly demonstrated that the diseased condition was transmissible, 

 and due to a specific micro-organism, which however he was unable 

 to isolate owing to defective technique. To this — now known as 

 the Bacillus cyanogenes of Hueppe — Fuchs gave the name of Vibrio 

 cyanogenes and subsequently Bacterium syncyaneuvi. In later 

 years it has been studied by many workers, especially by Neelsen 

 (1880), Hueppe, Fliigge, Heim, and Gessard, who showed that to 

 it, and as far as could be ascertained to it alone, the distinctive 



experimental grounds, by G. Tolomei, that it is caused by the action of ozone 

 produced by electrical discharges, is also unsupported by evidence. The effect 

 of thunderstorms on milk is almost certainly indirect. It is bacteria which 

 sour milk and the climatic conditions of a thunderstorm hasten their develop- 

 ment. 



^ For a discussion of fermentations allied to the coagulation processes see 

 Centralb.f. Bakt, iii. Bd., 1897, 615. 



