442 Bleached Flour [April-July 



Instead of using one drop of i percent sol. of potassium nitrite, 

 five drops (containing 5 mg.) were used. The blood of these 

 guinea pigs was examined spectroscopically, after three weeks' ad- 

 ministration of the nitrite sol., and also at intervals of three days, 

 but up to the present time (three months after the experiment was 

 begun), we have been unable to find any deviation from normal in 

 the blood of the guinea pigs that received the small dose, or in the 

 blood of the ones that received the large dose of potassium nitrite 

 sol. During this time two of our guinea pigs died, but autopsies 

 showed no conditions indicative of potassium nitrite poisoning, 

 death apparently resulting from natural causes. 



When we started the second series of guinea pig tests, we took 

 two pounds of unbleached flour, put it in a bottle, added two liters 

 of petroleum ether, and shook vigorously on a mechanical shaker 

 f or 24 hr. The mixture was then filtered through hard filter paper ; 

 the filtrate was greenish-yellow. We then passed peroxide of 

 nitrogen gas (obtained by the action of nitric acid on metallio 

 copper) through the liquid, completely decolorizing it, as well as 

 causing a grayish-white substance to be precipitated, which later, 

 on exposure to air, became brown in color and resinous in appear- 

 ance. This precipitate was obtained by filtration and washing re- 

 peatedly with petroleum ether. A little of this gave a pronounced 

 pink color with Greiss's reagent, showing the presence of nitrite. 

 The precipitate was slightly soluble in water, alcohol and the com- 

 mon solvents. 



The Liebermann test for nitrosamines was then made, as fol- 

 lows : A small amount of precipitate was placed in an evaporation 

 dish, several drops of conc. sulfuric, and conc. carbolic, acid added 

 and a greenish-red color obtained which, when diluted with water, 

 gave a red color. The addition of sodium hydroxid to alkalinity 

 caused a bluish-green color, showing the presence of a nitrosamine 

 or secondary amine. It is a question whether nitrite or nitrosamine 

 gives this color reaction. 



A rabbit was then fasted for two days and the precipitated 

 nitrosamine, obtained from two pounds of flour in the manner de- 

 scribed above, was rubbed up with a little water in a mortar and 

 introduced into the stomach by means of a catheter. The animal 



