220 BUTTER. 



is sufficient to bring on this sort of fermentation, and 

 of course render the products useless. 



579. However well butter is made, and however 

 thoroughly it has been washed, it always retains a 

 small portion of water and caseine ; and in conse- 

 quence of this it is apt to turn rancid and acquire a 

 bad flavor. If butter be carefully melted, these im- 

 purities will fall to the bottom, and may be sepa- 

 rated ; but though butter so treated keeps better, yet 

 it is always found that its flavor is slightly injured. 

 Clarified butter may be kept sweet for wrecks, and 

 even months, without the addition of salt. 



580. The yellow color of butter made in summer, 

 is derived from the grass and plants on which cows 

 feed. Winter butter is pale, or nearly colorless, 

 and often has a tallowy appearance. Such butter is 

 very frequently colored yellow by the addition of 

 annotto, carrot-juice, or some other yellow coloring 

 matter. These substances, though not unwholesome, 

 can only be regarded as adulterations, and are de- 

 cidedly objectionable. 



581. The tendency of butter to turn rancid is 

 much diminished by the use of a small quantity of 

 common salt. It must however, be remembered that, 

 though the bad flavor of butter which is very slightly 

 turned, may to some extent be covered or concealed 

 by the addition of salt, yet that its rancidity is not 

 thereby at all corrected or remedied. 



582. Cheese varies considerably in composition, 

 according to the mode in which it is prepared. When 



