212 Journal of Agricultural Research voi. m, no. 3 



tion of nitrates to the water did not cause the production of the red color 

 on the surface of the meat on boiling. This color was found to be soluble 

 in alcohol and ether and to give a spectrum showing an absorption band 

 just at the right of the D line, and a second band, often poorly defined, 

 at the left of the E line. On standing, the color of the solution changed 

 to brown and gave the spectrum of alkaline hematin. 



A color with similar properties was obtained on extracting hams and 

 various kinds of sausages with alcohol and other solvents. The author 

 named this coloring matter "hsemorrhodin." 



Kisskalt (1899) studied the production of red color in fresh meats on 

 cooking and found that this color appeared when meat was cooked in 

 bouillon which was several days old, or in water containing nitrites and 

 free acid. Meat boiled in water to which saltpeter had been added did not 

 take on the red color; but, on the other hand, if the meat was first allowed 

 to stand several days in contact v.'ith saltpeter and then boiled, the red 

 color appeared. 



Haldane (1901) made an extensive study of the color of cooked salted 

 meat, which color he concluded to be due to the presence of the nitric- 

 oxid hemochromogen resulting from the reduction of the coloring mat- 

 ter of the uncooked meat, or nitric-oxid hemoglobin (NO-hemoglobin). 

 This color was found to be the same as that resulting from the boiling of 

 fresh meat in water containing nitrites and free acid. It exhibited a 

 spectrum showing a distinct band just at the right of the D line and a 

 faint band a trifle to the left of the E line. The color was found to be 

 soluble in alcohol and in ether and to be quite resistant to the action of 

 reducing agents. 



The color of uncooked salted meats was found to be soluble in water 

 and gave a spectrum characteristic of NO-hemoglobin. The formation 

 of the red color in uncooked salted meats is explained by the action of 

 nitrites in the presence of a reducing agent and in the absence of oxygen 

 upon hemoglobin, the normal coloring matter of fresh meats. 



Orlow (1903) states that the red color of sausages is due to the action 

 upon the color of the fresh meat of the nitrites resulting from the re- 

 duction of the saltpeter used in the process of manufacture. 



The present author (1908) studied the action of saltpeter upon the 

 color of meat and found that the value of this agent in the curing of 

 meats depends upon its reduction to nitrites and nitric oxid, with the 

 consequent production of NO-hemoglobin, to which compound the red 

 color of salted meats is due. Saltpeter, as such, was found to have no 

 value as a flesh-color preservative. 



Glage (1909) is the author of a pamphlet concerning practical methods 

 for obtaining the best results from the use of saltpeter in the curing of 

 meats and in the manufacture of sausages. The fact that the value of 

 saltpeter as a flesh-color preservative is dependent upon the reduction of 

 the nitrate to nitrite is recognized, and directions are given for the 



