218 



OXY-H.EMOGLOBIN. 



The crystals obtained from the hgemofflobin of various animals 

 differ in their crystalline torn! The following figure shows some 

 of the most typical forms. 1 



FIG. 35. CRYSTALS OF OXY-HMOGLOBIN. (After Funke.) 

 a. Squirrel, b. Guinea-pig, c. Cat, or Dog, d. Man, e. Hamster. 



Apart from these differences in crystalline form the oxy-hsemo- 

 globin of different animals varies in its solubility, in the amount 

 of water of crystallisation with which its crystals are united, and 

 also apparently in its percentage composition. The crystals are 

 pleochroic but to a less extent than are those of haemoglobin. 2 

 As against these differences it is important to notice that the 

 close relationship of the various forms of oxy-hsemoglobin, from 

 whatever blood they may be obtained, is shown by the fact that 

 the spectroscopic properties are in all cases identical, as also are 

 the products of decomposition and the compoundL forme_d_yyith 

 ' ases! Numerous analyses^of oxy-haemoglobin have been made, 3 

 ut these while they tell us at most that it consists of oxygen, 

 hydrogen, nitrogen, and carbon together with iron as a character- 

 istic constituent and some* sulphur, and seem "to indicate that it 

 differs in composition as obtained from different animals, do^ not 

 as yet enable us to assign with any certainty a definite formula 

 to its composition, "it is nowever certain that its molecular 

 weight is enormously great (13,000 14,000). 4 



1 For a discussion of the various crystalline forms of oxy-haemoglobin see 

 Halliburton, Chem. Physiol. and Pathol. 1891, p. 270. 



2 A. Ewald, loc. cit. (sub haemoglobin). 



3 See Hammarsten's Lehrb. d. physiol. Chem. 1891, S. 57; or Halliburton's 

 Text-book of Chem. Physiol. Pathol. 1891, p. 286. 



* Marshall, Zt. f. physiol. Chem. Bd. vn. (1882), S. 81. Kiilz, Ibid. S. 384. 

 Cf. Zinoffsky, Ibid. Bd. x. (1886), S. 16, and see Hiifner, loc. cit. 



