SPECIAL EXAMINATIONS 375 



much slower process than the lactic one, and can also be 

 produced by some pathogenic anaerobes, e.g., bacilli 

 of quarter-evil, malignant oedema, B. Welchii and B. 

 enteritidis sporogenes (Klein). 



Alcoholic Fermentation of milk occurs spontaneously 

 on rare occasions. The process is due to the natural in- 

 troduction of yeasts, and once started can be kept going 

 by infecting fresh milk. Koumiss is thus made by the 

 Tartars from mare's milk. Kefir is an effervescent sour 

 milk made from cow's milk by the addition of " kefir 

 grains," little cauliflower-like excrescences whose fermen- 

 tative power is due to Saccharomyces mycoderma. Mare's 

 milk is more suitable for the preparation, because the 

 lactic fermentation also accompanies the other, and the 

 duration of the double fermentation is conditioned by the 

 amount of sugar, which is 5-5 per cent in mare's milk and 

 4-8 per cent in cow's. The latter is richer in casein and fat, 

 and both of these constitute disadvantages, so that it is 

 usually diluted in making koumiss. In the making, the 

 milk is stirred constantly by day but rested at night. The 

 amount of alcohol in all these products koumiss, kefir, and 

 cow's milk koumiss is under 2 per cent, and the Tartar is 

 capable of consuming three to four gallons of such milk 

 on a hot summer's day without becoming more than 

 hilarious, and with no digestive disturbance. They have 

 been much used as " consumption cures." 



Diseases of Milk. 



Unusual or abnormal changes in milk are sometimes 

 referred to as " diseases." They are produced by bacteria 

 which have got into milk in various ways. Blue, green, 

 and yellow milks are due respectively to the bacilli cyano- 

 genes, erythrogenes, and synxanthus ; and red milk to 

 B. prodigiosus. Bitter milk is due to a number of 

 species, yeasts and diplococci having been isolated. 

 Slimy or ropy milk has been traced to B. lactis viscosus, 

 said to be a water organism. Slimy milk is produced 

 at Edam (Holland) by the use of a streptococcus, for 

 the manufacture of Edam cheese. Soapy milk is due to a 

 micrococcus derived from fodder. 



