146 



EXPERIMENT STATION. 



[Jan. 



dilute phosphoric acid into bromine water. The excess of bro- 

 mine was then boiled o& and the sulphuric acid formed deter- 

 mined by precipitation with barium chloride. The distillation 

 was conducted in the presence of carbon dioxide, which served 

 to i^revent oxidization. Dilute coi:)per sulfate solution^ was 

 used to purify the suljjhur dioxide. Since it was necessary to 

 employ relatively large amounts of the sample for distillation, 

 it was found convenient to place the distilling flask on an oil 

 bath to prevent burning. The following table gives the result 

 of several determinations : — 



Niunber of Sample. 



1, . 



2, . 

 8, . 



4, . 



5, . 



Sulphur Dioxide (Per Cent.). 

 .OU50 



.0008 



.00-10 



.0006 

 none 



Dkuik .UOU.J ill each case. 



The results of these various analyses show that the amount of 

 sulphurous acid in the samples of gluten feeds tested was small, 

 and it can be assumed that practically all of the sulphurous acid 

 originally added has been driven off or oxidized to sulj^huric 

 acid. Formerly the United States government allowed the addi- 

 tion of sulphur dioxide to foods at the rate of 350 milligrams 

 per kilogram, or .035 of a gram per 100.- This decision was 

 later amended,^ pending determination by the referee board, 

 and at present calls for the labeling of all foods containing even 

 small amounts of sulj^hur dioxide. 



4. Coloring Matter. 



In the work presented on coloring matters no attempt has 

 been made to determine the individual dye or combination of 

 dyes used, but rather to ascertain whether the added color was 

 one of vegetable or coal tar origin. The method for the detec- 

 tion of artificial coloring matter in gluten feeds recommended 

 by Gudeman^ is not applicable in those cases where the sub- 



' Winton and Bailey, Journal American Chemical Society, Vol. XXIX., No. 10, 149'.). 



2 Food iiispeotion derision No. Tfi, .Inly 13, l'.)07. 



» Food inspcftion decision No. S'.», Felj. 2H, I'MH. 



* Journal American Clieniical Society, Vol. XXX., No. 10 (1!)08), 1623. 



