Dec. 15, I9I4 Coloring Matter of Salted Meats 2 1 7 



The above method was followed for the crystallization of both oxy- 

 hemoglobin and NO-hemoglobin from sheep, ox, and pig blood, and of 

 methemoglobin from ox blood. It was found practically impossible to 

 secure crystals of hemoglobin or of its derivatives from the blood of 

 the above-mentioned animals without the use of ammonium oxalate. 

 It was also found necessary to carry on the work at a temperature 

 slightly above freezing, since the crystals would not form readily at 

 room temperature. 



Ox-blood oxyhemoglobin. — Plate XXXII, figures i and 2, shows 

 crystals of oxyhemoglobin from ox blood. These crystals correspond 

 very closely with those described by Reichert and Brown. No attempt 

 was made to make a critical study of the crystallography of any of the 

 various hemoglobin compounds studied. 



Ox-blood NO-hemoglobin. — Plate XXXII, figure 3, shows crystals 

 of this compound. It was found very difficult to obtain crystals of 

 NO-hemoglobin, owing, apparently, to its greater solubility as compared 

 with oxyhemoglobin. The crystalUne structure, it will be noted, is 

 distinctly different from that of oxyhemoglobin. 



Ox-blood methemoglobin. — Plate XXXII, figures 4 and 5, shows 

 crystals of this compound which were prepared by treating oxyhemo- 

 globin with potassium ferricyanid. It will be noted that the crystals of 

 this compound are very similar in structure to those of NO-hemoglobin. 



Sheep-blood oxyhemoglobin. ^Plate XXXIII, figures i and 2, 

 shows crystals of this compound which correspond very closely with 

 those described by Reichert and Brown. 



Sheep-blood NO-hemoglobin. — It was not found possible to secure 

 a thoroughly satisfactory mount of these crystals, owing to their high 

 solubility. Plate XXXIII, figure 3, shows fair crystals of this com- 

 pound in the form of plates, which, however, are largely obscured by the 

 large crystals of ammonium oxalate. It may be noted, however, that the 

 crystals of NO-hemoglobin are distinctly different from those of oxy- 

 hemoglobin from the same source. 



Pig-blood NO-hemoglobin. — Plate XXXIII, figures 4 and 5, shows 

 crystals of NO-hemoglobin obtained from pig's blood. It was not found 

 possible to secure a good mount of oxyhemoglobin crystals from pig's 

 blood, but the NO-hemoglobin crystals shown in this illustration are very 

 different in structure from the oxyhemoglobin crystals from pig's blood 

 described by Reichert and Brown. 



The above work shows that NO-hemoglobin derived from ox, sheep, 

 and pig blood is a crystallizable compound, with a definite structure, 

 depending upon the species from which it has been obtained, and that 

 its structure is different from oxyhemoglobin crystals from the same 

 sources. 



