HEMOGLOBIN AND ITS DERIVATIVES. 107 



1. Xanthoproteic. 



2. Insolubility in hot and cold water. 



240. Let a shred of washed fibrin stand for an hour 

 or two in a test-tube with 0.1 per cent. HC1. It swells up 

 and becomes transparent, but does not dissolve. Warm 

 at 60 to 70 for several hours; filter and test the filtrate 

 for acid albumin by neutralizing. 



241. Dissolve a little dried blood in nitric acid with 

 the aid of heat. Filter and test the filtrate for iron with 

 potassium ferrocyanid, which produces a blue color. 



HEMOGLOBIN AND ITS DERIVATIVES. 



I. HEMOGLOBIN: Composed of an albuminous substance 



and an iron compound, haemochromogen. 



II. OXYHEMOGLOBIN: A compound of oxygen with haemo- 



globin. 



III. METHEMOGLOBIN: Composition same as oxyhaemo- 



globin. Different arrangement of the atoms. 



IV. HEMATIN: The iron compound united with albu- 



minous substance in oxyhsemoglobin. Haemochro- 

 mogen plus oxygen. 



V. HEMIN: A compound of haematin with HC1, one 



molecule of each. 



VI. HEMOCHROMOGEN: Haemoglobin minus its albumin- 



ous constituent. With oxygen it gives haematin. 



VII. HEMATOPORPHYRIN: Formed by the removal of 

 iron from haematin, haemin, etc. 



HEMOGLOBIN. 



Haemoglobin, sometimes called reduced haemoglobin, 

 is the coloring matter of venous blood. It contains iron, 

 besides the elements which enter into the composition of 

 albuminous substances. The constitution of the mole- 



