236 MYOILEMATIN. 



Myohcematin^ . To observe the spectrum of this substance a slice 

 of tissue, such as that of the heart, is squeezed in a compressoriurn 

 until sufficiently thin to transmit light. It is then examined with a 

 microspectroscope under strong illumination. Or, on the other hand, 

 the tissue may be treated with excess of ether under whose influence 

 an aqueous juice is extruded in which the myohsematin is in solution. 

 Speaking generally, for the appearances vary slightly according to the 

 source of the pigment, myohsematin yields a four-banded absorption 

 spectrum. The first band lies close to D, but towards the red end of 

 the spectrum. The next two bands are situated close together about 

 midway between D and E. The remaining band lies in the region 

 between E and b. Solutions of myohsematin are when weak of a 

 reddish-yellow colour, but if strong they are pure red. By the action 

 of warm alcohol containing a little sulphuric acid a spectrum is obtained 

 closely similar to that of hsematin in acid solution, and by the use of 

 concentrated sulphuric acid a substance is produced which in both acid 

 and alkaline solutions shows bands similar to those of hsematoporphyrin 

 in the same solvents. Under certain conditions myohsematin becomes 

 ' modified' and now yields two bands similar to those of hsemochromogeii, 

 but situated nearer the violet end of the spectrum. 



The conclusions drawn from the above spectroscopic facts have 

 been the subject of some controversy and adverse criticism, the ap- 

 pearances being regarded as due not to a specific pigment, but rather 

 to hsemochromogen or mixtures of other products of the decomposition 

 of haemoglobin 2 . 



11. Haemin. C 34 H 35 N 4 Fe0 5 . HC1. (Hsematin-hydrochloride or 

 Teichmann's crystals.) 



These crystals may be readily obtained for microscopic examination 

 by heating a drop of fresh blood on a glass^slide under a cover-slip with 

 a little glacial acetic acid 3 . In the case of blood which has been dried, 

 as in an old blood-clot or stain, the residue should be powdered as finely 



" 



Fig. 38. H^MIN CKYSTALS FROM A DROP OF BLOOD. (Kiihne.) 



1 MacMunn, Phil. Trans. Pt. i. 1886, p. 267, Jl. of PhysioL Vol. vm. (1887), 

 p. 51. 



2 Levy, Zt. f. physiol Cliem. Bd. xm. (1889), S. 309. Hoppe-Seyler, Ibid. Bd. 

 xiv. (1890), S. 106. For reply see MacMunn, Ibid. xm. S. 497, xiv. 328. 



3 Teichmann, Zt. f. rat. Med. Bd. in. (1853), S. 375, Bd. vm. S. 141. 



