DERIVATIVES OF HEMOGLOBIN 141 



If the readings obtained with the large cell are exactly correct, then the read- 

 ings with the smaller one should be 43.2, since 54 X | =43- 2 - Or, if the 

 readings with the smaller cells are exact, the readings with the larger should 

 be 52 . 5, since 42 Xf = 52 . 5. Hence the mean of 54 and 52 . 5, namely 53 . 25, 

 should be taken as the correct figure. On looking at the corrected table of 

 hemoglobin values supplied with each instrument, we would find that this 

 number on the scale corresponds to a solution containing 400 milligrams 

 of hemoglobin per 1000 cubic centimeters of solution. But our original dilu- 

 tion was either i: 200, i: 300, or o: 400, according as our pipet had been 

 filled with blood up to the mark |, f , or J; so that in order to obtain the actual 

 percentage of hemoglobin in the blood under examination we should be 

 obliged to multiply our results by 200, 300, or 400. In the example we have 

 taken, the amount of hemoglobin would be, if our dilution was i : 200, 400 X 

 200=80,000 milligrams = 80 grams in 1,000 cubic centimeters =8 grams 

 in 100 cubic centimeters, or 8 per cent. 



Another very simple method of approximately determining the hemo- 

 globin percentage is the hemoglobin scale devised by T. W. Talquist. This 

 consists of a series of shades of color corresponding to undiluted blood of 

 various hemoglobin values, ranging from 10 to 100 per cent, of an 

 arbitrary scale. This scale is included in a book, the remaining pages of 

 which consist of filter-paper, which is used for absorbing the specimen of 

 blood whose hemoglobin percentage is to be estimated. The blood-stained 

 filter-paper is compared with the hemoglobin scale by direct daylight until 

 a shade is found with which it corresponds. For approximate results this 

 method has proved very satisfactory. 



Derivatives of Hemoglobin. Hematin. By the action of heat or 

 of acids or alkalies in the presence of oxygen, hemoglobin can be split up 

 into a substance called hematin, which contains all the iron of the hemo- 

 globin from which it was derived, and a protein residue, a histone, globin. 

 If there be no oxygen present, instead of hematin a body called hemochro- 

 mogen is produced, which, however, will speedily undergo oxidation into 

 hematin. 



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

 metallic luster. Its percentage composition is C, 64.30; H, 5.50; N, 9.06; 

 Fe, 8.82; O, 12.32; which gives the formula C 68 H 70 N 8 Fe 2 O 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 hematin by heating it with fuming 

 hydrochloric acid to 160 C., and a new body, hematoporphyrin, the so-called 

 iron-free hematin, is produced. Hematoporphyrin (C 68 H 74 N 8 O 12 , 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 spectrum, viz., a dark band just beyond D, 



