306 MASSACHUSETTS AGRICULTURE. 



propose to treat on these important points here in detail, but 

 intend to confine myself to a short discussion of those qualities 

 of milk which affect its commercial value, and to describe a few 

 of the methods for testing it. The constituents of a normal 

 milk have been found to vary, usually, within the following fig- 

 ures: 



100 100 



Its solid matter has been noticed to vary in extreme cases, 

 even from 11.0 to 16.8 per cent., and its specific gravity from 

 1.026 to 1.034 at 60° F., taking water of that temperature equal 

 to 1.0. As the presence of butter has a tendency to lower the 

 specific gravity, and the presence of casein, sugar and saline 

 matter reacts in the opposite direction, and as all these various 

 constituents are liable to vary in percentage, it is plain that no 

 reliable deduction can be drawn in regard to the total amount 

 of solid matter in milk, from a mere test of its specific gravity. 

 Skimmed milk of a high specific gravity — 1.0338 to 1.0347 — 

 contains ordinarily but from 10 to 11.1 per cent, of solid matter ; 

 while a milk unusually rich in cream of a specific gravity equal 

 to 1.026, has been shown to contain not less than 16.8 per cent, 

 of solid matter. A common, good, unadulterated milk has a 

 specific gravity from 1.029 to 1.033, and contains from 11 to 14 

 per cent, of solid matter. These facts in regard to the composi- 

 tion of milk render it certain that the common practice of decid- 

 ing the question, " what is genuine milk, and what is watered 

 milk ?" is open to serious objection, unless supported by a sup- 

 plementary test, since it is liable to awaken an unjust suspicion 

 of fradulent practices on the dealer, while it does not efficiently 

 protect the consumer against serious imposition. To protect 

 the dealer against unjust accusations of dishonesty, the scale of 

 specific gravity had to be lowered to a degree (1.026) which 

 would leave it possible for him to add at least one-fourth of wa- 

 ter to an ordinary good milk, without rendering himself open 

 to the suspicion of fraud. There is little reason with us to fear 



