THE BLOOD. 



was derived, and a proteid residue. Of the latter it is impossible to say 

 more than that it probably consists of one or more bodies of the globulin 

 class. If there be no oxygen present, instead of haematin a body called 

 haemochrpmogen is produced, which, however, will speedily undergo 

 oxidation into ha3matin. 



Ha3matin is a dark brownish or black non-crystallizable substance of 

 metallic lustre. Its percentage composition is C. 64.30; H. 5.50; N. 

 9.06; Fe. 8.82; 0, 12.32; which gives the formula C 68 , H 70 , N" 8 , Fe f , 10 

 (Hoppe-Seyler). It is insoluble in water, alcohol, and ether; soluble in 

 the caustic alkalies; soluble with difficulty in hot alcohol to which is 

 added sulphuric acid. The iron may be removed from haematin by 

 heating it with fuming hydrochloric acid to 320 F. (160 C.), and a 

 new body, haematoporphyrin, is produced. Hagmatoporphyrin (C 6 X 8 , 

 H 74 , N 8 , 0,,, Hoppe-Seyler) may also be obtained by adding 'blood to 

 strong sulphuric acid, and if necessary filtering the fluid through 

 asbestos. It forms a fine crimson solution, which has a distinct spec- 

 trum, viz., a dark band just beyond D, and a second all but midway 

 between D and E. It may be precipitated from its acid solution by adding 

 water or by neutralization, and when redissolved in alkalies presents 



I 



FIG. 81. FIG. 82. 



FIG. 81. Haematoidin crystals. (Frey.) 

 FIG. 82. Haemin crystals. (Frey.) 



four bands, a pale band between c and D, a second between D and E, 

 nearer D, another nearer E, and a fourth occupying the chief part of 

 the space between b and F. 



Hcematin in acid solution. If an excess o"f acetic acid be added to 

 blood, and the solution is boiled, the color alters to brown from decom- 

 position of haemoglobin and the setting free of haematin; by shaking this 

 solution with ether, solution of the haematin in acid solution is obtained. 

 The spectrum of the ethereal solution (colored plate) shows no less than 

 four absorption bands, viz., one in the red between c and D, one faint 

 and narrow close to D, and then two broader bands, one between D and 

 E, and another nearly midway between b and F. The first band is by far 

 the most distinct, and the acid aqueous solution of haematin shows it 

 plainly. 



Hcematin in alkaline solution. If an alkali be added to blood and 

 the solution is boiled, alkaline haematin is produced, and the solution 

 becomes olive green in color, the absorption band of which is still in the 

 red, but nearer to D, and the blue end of the spectrum is partially 

 absorbed to a considerable extent. If a reducing agent be added, two 

 bands resembling those of oxy-haemoglobin, but nearer to the blue, 

 appear; this is the spectrum of reduced hcematin, or haemochromogen. 



