ITS PHYSICAL, CHEMICAL, AND STRUCTURAL CHARACTERS. 249 



ble of existing in two states of oxidation, distinguishable by a difference <>f 

 color and a fundamental difference in the action on the spectrum. To this 

 coloring matter he has applied the term Cruorin, suggested by Dr. Sharpcy, 

 its two states of oxidation being termed scarlet cruorin and purple cru- 

 orin respectively. Prof. Stokes showed also that hcematin, which is the re- 

 sult of the action of weak acids on cruoriu, was similarly capable of oxida- 

 tion and reduction, and that it shows well-defined and highly characteristic 



9 10 11 12 



Rod 

 eud. 



1. Sorby's standard interference 

 spectrum. 



2. Oxidized haemoglobin or scar- 

 let cruoriu. 



3. Haemoglobin with carbonic 

 oxide. 



4. Deoxidized haemoglobin or 

 purple cruorin. 



5. Old blood-stain in water. 



6. Hfernatiii in an acid solution. 



7. Homiatin in an ammoniacal 

 solution. 



8. Deoxidized ammoniacal hsem- 



atin. 



9. Fraunbo'fer's lines. 



Blue 

 end. 



A B e D 



E b 



lines, which, however, are by no means identical with those of cruorin. Prof. 

 Stokes suggests, as a physiological deduction from his experiments, that cru- 

 orin is to "be regarded as the carrier of oxygen to the tissues, since it absorbs 

 that gas with extreme facility; whilst under the influence of reducing agents, 

 it permits it again to be withdrawn from it. Both Hoppe and Stokes refer to 

 the applicability of spectrum analysis for the detection of blood-stains in med- 

 ico-legal investigations. Mr. Sorby 1 has greatly improved the mechanical 



1 Quart. Journ. of Sci., 1865, vol. ii, p. 198; Pop. Sci. Review, vol. v, p. 06; 

 Proceed, of Roy. Soc., vol. xv, 1866-7, p. 433. For an account of V T ierordt's method 

 of notation see'Dalton, N. Y. Med. Journ., vol. xix, 1874, p. 579. 



17 



