DIRTY MILK 85 



sufficient number to cause souring. Such milk may, there- 

 fore, putrefy with age. Thus we have actually found that 

 the best samples of certified milk which have been exam- 

 ined in my laboratory did not contain nature's danger 

 signal, and when kept a long time did not sour nor- 

 mally, but underwent the less desirable form of decompo- 

 sition. 



The use of sour milk has recently come into vogue 

 through the teachings of Metchnikoff, who called atten- 

 tion to the importance of the normal acid-producing flora 

 in the large intestines and recommended the use of certain 

 bacteria in sour milk, especially the Bacillus bulgaricits. 

 It is a fallacy to suppose that the flora of the large intes- 

 tines may be materially influenced by the ingestion of 

 these bacteria, even though they are taken in enormous 

 numbers such as the countless myriads present in sour 

 milk. For example, a sour milk may contain several bil- 

 lion bacteria in each cubic centimetre. The number in a 

 glassful would scarcely be equaled by the stars in the hea- 

 vens. The best way to change the intestinal flora is through 

 diet. With a carbohydrate diet these acid-producing or- 

 ganisms gain the ascendancy and keep back protein putre- 

 faction and in that way tend to prevent what is known as 

 auto-intoxication. 



Colored milk 



Blue milk is usually caused by the Bacillus cyanogenes. 

 Such milk is apparently harmless. Red milk may be due 

 to the presence of blood. The blood comes either from an 

 injury to the udder or some acute inflammatory disease. 

 A reddish color in milk may also result from the feeding of 

 the cows on plants containing red pigment, such as the 

 madder root. A red color will also be produced by the 

 Bacillus erythrogenus, the Bacillus prodigiosus, or certain 

 sarcinse. The production of red milk through the agency 

 of bacteria is without sanitary significance. 



