DETECTION OF ADULTERATION 223 



specific- gravity of the solids (m) must be increased. The 

 specific gravity of adulterated milk can vary consider- 

 ably, often it is nearly normal, but frequently it is 

 slightly diminished. Feser has given the following ex- 

 ample of such adulteration : 



The unadulterated milk had 3.05 per cent., fat; 8.9 

 lier cent., solids not fat; 1.031 specific gravity; by par- 

 tial skimming, it was changed to 2.19 per cent., fat; 

 about 8.9 per cent., solids not fat; 1.034, specific gravity; 

 by the addition of water it was further changed to 1.21 

 per cent., fat; about S per cent., fat free solids; l.(l30."j, 

 specific gravit.\'. 



Decisive points for determining if such adulterations 

 exist are the low solid contents, the low fat i)er cent., 

 the almost normal specific gravity of the milk, the in- 

 creased specific gravity of the solids (m) which, in the 

 above exami)le, was changed from l..'!0,") to 1.473, and in 

 the low specific gravity <if the whey. If nitrates arc 

 proven in the milk tliere is further suppcu't for tlic coti- 

 elusion that it is watered. 



"When a sample of adulterated milk can fairly be 

 compared with another which is known to be unadulter- 

 ated (samples taken from the same dealer the same day, 

 milk of a large herd, etc.) [or with an accepted stand- 

 ard] one can form an opinion of the extent of the 

 adulteration by means of a formula derived from Bohm- 

 liinder : 



:\i - - ^^ X w — Av 



r 



1(1(1 



(■-;■:) 



M shows the quantity of water added to 100 grm. of 

 milk; W is the per cent, of water in the unadulterated 

 and w in the adulterated, or suspected, sample; E and r 

 are the jtereentages in these two samples of solids not 



