FEEDING VALUE OF SKIM MILK. 103 



senting those breeds as a whole. I do not wish to convey that im- 

 pression at all. I simpl}' give these figures as representing two 

 animals of each breed which we have at the State College farm, and 

 we have good animals there. Suppose then you were to take a hun- 

 dred pouEds of milk from each of the breeds I have named. You 

 would find varying quantities of this solid matter left in the dish out 

 of which you liad driven the water, in the Shorthorn 12.80, Holstein 

 12.10, Ayrshire 12.85 and Jersey 14.85 parts in 100. One of 

 the constituents of milk, and an important one in skim milk, is 

 what we call caseine. It is important from the food standpoint 

 especially, whether the milk in which it is contained is used for man 

 or animals. All the muscular tissue of our bodies is built out of 

 this constituent, so far as we take milk for food. It is built, I say, 

 out of this ingredient, or a similar ingredient in some other kind rl 

 food, and it is the nitrogenous part. It is that which gives muscular 

 fibre, and tendons in the animal body. Now I have represented 

 here in these glass tubes the actual amount of that constituent of 

 milk as found in the three breeds of Holstein, Ayrshire and Jersey, 

 and the varying lengths of the tubes is almost the exact measure of 

 the relative amounts of that ingredient as found in the three kinds 

 of milk. We speak of the A3'rshire as an animal giving a large 

 amount of chees}' matter. "Well, that is true if you consider the 

 Ayrshire milk with reference to the whole quantit}- of milk given, 

 and not with reference to the relative amount. At least, we have 

 two Ayrshires sent to us by the secretary of the Ayrshire Associa- 

 tion, Mr. Winslow, which he said he was willing to have taken as 

 typical Ayrshires and those cows in a quart of milk are not giving 

 as much caseine and albamen as our Jerseys are. They are giving 

 more milk, considerably so, and when you consider the question of 

 the total amount|of this constituent produced, that is another thing. 

 I am simply giving the amount of material in one quart of milk. 



Then there is found in milk what is called milk sugar, and a 

 larger amount of it than of any other constituent. This is true of 

 all three breeds except the Jersey, which runs a little higher in fat. 

 Sugar of/^^milk has almost the same composition as the sugar 

 used on your table or in cooking, and has the same food value. 

 But it has a very different taste. If you were to take some of that 

 solid sugar in your mouth you would scarcely recognize it as sugar. 

 The material in these tubes represents the amount of sugar in a 

 quart of milk, the Jersey having the least, the Ayrshire the most. 



