HEMOGLOBIN DERIVATIVES. 115 



and take its place. Consequently the haemoglobin is ren- 

 dered useless as a carrier of oxygen, and cases of poisoning 

 by coal-gas, which contains carbon monoxid, are often fol- 

 lowed by fatal results. The compound has a two-band 

 spectrum much like that of oxyhsemoglobin, but differs in 

 not being changed to hemoglobin by reducing agents. The 

 crystals are similar to those of oxyhaBmoglobin, but more 

 of a bluish red. When mixed with strong sodium hydrate 

 solution blood containing carbonic oxid gives a red mass, 

 while pure blood turns brown, with a greenish cast. 



HEMOCHROMOGEN. 



As the oxyhaemoglobin by the action of acids or alkalies is 

 decomposed into an albuminous substance and hsematin, so by the 

 same agencies haemoglobin gives an albuminous substance and 

 hsemochromogen. The latter in the presence of free oxygen is 

 converted into hsematin. Hence, as we should expect, by the re- 

 moval of oxygen from hsematin by the aid of reducing agents we 

 obtain hsemochromogen. The spectrum of hsemochromogen, in an 

 alkaline solution, has two bands similar to those of oxyheemo- 

 globin, but a little farther toward the blue. The color of the 

 alkaline solution is a cherry red. It is often seen in alcoholic 

 specimens of the liver, muscles, etc., w r hich have stood for a time 

 in alcohol. 



HEMATOPORPHYRIN. 



By the action of acids upon haematin the iron is removed, 

 leaving a violet to red coloring matter hsematoporphyrin. It is 

 found in the contents of the stomach and intestine after poisoning 

 with strong acids. It also is found in some of the dark-colored 

 urines. It is insoluble in water, more soluble in acids, and easily 

 so in alkalies. 



243. Add enough blood to a little water to color it 

 a bright red. Dissolve a small crystal of ferrous sulphate 

 and as much tartaric acid in 10 cubic centimeters of water, 



