50 Milk and Its Products 



It goes without saying that a ration cannot be of 

 the highest degree of effectiveness if it is not pala- 

 table, if the animal does not eat it, not only readily 

 but eagerly. The factors of palatability are not well 

 understood, nor always easily recognized, and our 

 knowledge of them is to a very considerable extent 

 empirical, and the result of actual observation and 

 experience. About all that can be said in this respect 

 is that of two rations or combinations of food similar 

 in all other respects, that one will be most effective 

 that is most readily eaten by the animal. There are 

 certain adventitious aids to palatability, such as salt, 

 water or succulence, and freshness. The peculiar char- 

 acteristics of certain plants also make them particu- 

 larly palatable or unpalatable for certain animals, or 

 classes of animals, and in addition there are various 

 vegetable aromatics and semi -tonics, and certain inor- 

 ganic salts, that are recognized as having a marked 

 effect upon the appetite. A continuous use of these 

 latter for healthy animals seldom results in distinct 

 advantage. The secretion of milk seems to be inti- 

 mately connected with < the water content of the food. 

 Milk itself is a watery substance (ordinarily about 

 seven -eighths water), and of course the water, which 

 makes up so large a part of it, demands a corres- 

 ponding consumption of water by the animal. It 

 seems almost necessary that a certain part of this 

 water should be regularly incorporated with the food 

 or, in other words, it is of great advantage for the 

 secretion of milk that at least a part of the food 

 should be composed of materials .containing large 



