HEMOGLOBIN-DERIVATIVES 507 



THE DISSOCIATION-PRODUCTS OF HAEMOGLOBIN 



On adding to a salt-free solution of pure haemoglobin a few drops 

 of very dilute acid the haemoglobin is split up into globin and haematin, 

 according to Hoppe-Seyler, 1 Stokes, 2 Preyer, 3 Schulz, 4 and Lawrow. 5 

 Harnack's intermediate * acid-haemoglobin ' has already been discussed 

 on p. 495. The 'globin' of Schulz is prepared as follows : A salt- 

 free haemoglobin solution is dissociated by a little acid ; then alcohol 

 and ether are added. The haematin passes into the ether, while the 

 globin remains in the watery alcohol solution. Other observers 

 have proceeded similarly, but if globin is not wanted as such, salt 

 may be added, the solution may be boiled, the amount of acid be 

 varied, etc., when instead of globin there are formed acid-albumin or 

 *even more remote transformation-products. v. Zeynek 6 brought 

 about dissociation with pepsin-hydrochloric acid, when the albumin is 

 dissociated into peptones, while the haematin separates out as an 

 insoluble mass. 



By stronger alkalies, or by boiling, haemoglobin is also split up 

 into haematin and albumin. According to Schulz, 100 parts of haemo- 

 globin give rise to 86*5 parts of globin and 4*2 parts of haematin; of 

 the unknown remainder a certain fraction belongs to the globin. 

 Lawrow found 9 4 '09 per cent globin, 4*47 per cent haematin, and 

 only 1*44 per cent unknown bodies, amongst which he could demon- 

 strate fatty acids and ammonia. Hoppe-Seyler, on dissociating hemo- 

 globin, has also observed the occurrence of formic, butyric, and other 

 acids of the fatty series. The union between globin and haematin must 

 be an exceedingly feeble one, as the minutest trace of an acid at once 

 causes dissociation. Notwithstanding this ready dissociation, we are 

 dealing with a true salt formation, as the globin may be replaced by 

 egg-white, according to Ham and Baleau, 7 who believe haematin to be 

 an acetyl-compound or similar derivative, but see p. 509. The union 

 between the haematin and the globin, according to Hoppe-Seyler, is 

 an esterlike one, and Htifner 8 also holds that the globin and haematin 

 are kept together by one or several atoms of oxygen acting as the link. 



1 F. Hoppe-Seyler, Virchow's Arch. 29. 233 (1864); Zentralbl. f. d. med. 

 Wissensch. 1864, p. 261 ; 1865, p. 65. 



2 G. G. Stokes, Philosoph. Magaz. 27. 4 Ser. 388 (1864). 



3 W. Preyer, Pftiiger's Arch. f. d. gescunte Physiol. 1. 395 (1868) ; Die Blutkris- 

 talle, Jena, 1871. 4 F. N. Schulz, Zeitschr.f. physiol. Ghem. 24. 449 (1898). 



5 D. Lawrow, ibid. 26. 343 (1898). 6 E. v. Zeynek, ibid. 30. 126 (1900). 



7 C. E. Ham and H. Baleau, Journ. of Physiol. 32. 312 (1905). 



8 G. Hiifner, Arch. f. (Anat. .) Physiol. 1899, p. 491. 



