190U.] 



rUBLIC DOCUMENT — No. 31. 



145 



Acidity calculated as Sulphuric Acid. 



Number of Feed. 



432, 

 433, 

 434, 

 435, 

 436, 

 437, 

 438, 

 439, 

 440, 

 441, 

 442, 

 443, 

 444, 

 445, 

 446, 

 447, 



Acidity to 



Phenolphtha- 



lein. 



.10 

 .14 



.7'J 

 .(K! 

 • 77 

 aw 

 i.ou 



.06 



1.4S 



.06 



.70 



.92 



.06 



1.06 



1.06 



.87 



Acidity 



to Methyl 



Orange. 



Number of Feed. 



448, 

 449, 

 450, 

 451, 

 452, 

 4.53, 

 454, 

 4.55, 

 456, 

 457, 

 458, 

 459, 

 460, 

 461, 

 462, 



Acidity to 



Phenolphtha- 



leiii. 



Acidity 



to Methyl 



Orange. 



2.24 

 1.11 



.84 

 .92 



1.38 

 .50 

 .03 

 .18 

 .08 



1.09 



1.60 

 .78 



1.53 

 .08 



2.11 



The several titrations indicate that in every case the water 

 solutions of the feed gave a neutral or alkaline reaction with 

 methyl orange. Methyl orange as an indicator possesses rather 

 strong acid properties, i.e., it forms compounds that are quite 

 stable and which require strong acids to decompose them, hence 

 it is much more sensitive to free inorganic acids than to those 

 of an organic nature, some of the latter being entirely unable to 

 replace the acid radical of the indicator. 



3. Sulfites. 



In the process of manufacture of gluten feed there is, as has 

 been heretofore stated, a certain amount of sulphurous acid 

 added to facilitate the separation of the various parts of the 

 corn. Since sulfites are of a poisonous character it was im- 

 portant to determine whether they were present in the finished 

 feed in sufiiciently large amounts to cause any serious results 

 when fed to animals. Sulfites were determined after the usual 

 method, by distilling a considerable amount (50 grams) with 



