THE KINDS OF MICRO-ORGANISMS IN MILK 387 



heat the metal, will usually suffice, but the application of steam 

 as usually practised is not always sufficient. Sometimes even 

 pasteurized milk may suffer from some extraordinary bacterial 

 infection, as some bacteria are more heat resistant than others 

 and may slip through the apparatus. Later they multiply and 

 cause an abnormal appearance or taste in the milk. The pas- 

 teurizer and other machinery may be filled with milk of lime, 

 which is allowed to remain for several hours and is then washed 

 out with hot water. 



Disinfection of stables may become necessary because of the 

 presence of obnoxious or infectious micro-organisms. The germi- 

 cidal agent must, of course, penetrate all crevices and openings, 

 and proper preparation of the stable should precede the actual 

 application of the germicide. All food, bedding, manure, and 

 other material must be removed, and the surfaces of walls, ceil- 

 ing, mangers, stalls, floor, etc., scraped to free them from adher- 

 ing or caked substances. Dust and cobwebs must be swept away. 

 In places where wood has decayed it should be replaced by sound 

 material, because such places offer special opportunity for germs 

 to lodge. The removed wood should be burned to destroy the 

 infectious material. Water-troughs and mangers require special 

 attention, as they are difficult to clean thoroughly. The barn- 

 yard should be cleaned and covered with a layer of dry straw or 

 other inflammable material, which is then burned. 



There are several efficient germicides from which to choose 

 for disinfecting stables. Compound solution of cresol (Liquor 

 cresolis compositus, U. S. P.) is a good disinfectant. It is com- 

 posed of equal parts of cresol and linseed-oil-potash soap and is 

 easily soluble in water. In each gallon of water 4 to 5 ounces of 

 this compound should be dissolved. 



Mercuric chlorid is perhaps the most reliable stable disinfec-. 

 tant, but has the disadvantage of being a violent poison, so that 

 great care is necessary in handling it. After it has been used the 

 mangers and water-troughs must be washed with water to remove 

 the poison. 



Chlorid of lime may be used in proportion of 6 ounces to 1 

 gallon of water, but is objectionable because of the odor and the 

 uncertainty of strength of the commercial product. The same 

 may be said about crude carbolic acid. 



Formaldehyd gas liberated by addition of potassium per- 

 manganate is a powerful disinfectant of great penetrating power, 

 but efficient only when the stable can be sealed nearly air-tight. 

 Under ordinary conditions this is a difficult thing to accomplish. 



Cresol is also a good disinfectant, but dissolves in water with 

 considerable difficulty. A 2 per cent, solution of cresol in hot 



