vii ALDEHYDE- AND IRON-COMPOUNDS 251 



plurivalent alcohols such as sugars, and with aromatic alcohols such 

 as recorsin. 



Bechhold l has described a phosphoric acid ester of albumins. 



IRON COMPOUNDS OF ALBUMINS 



In addition to the salts which albumins form with different metals 

 in their ionic state, and also with ionic iron, there exist also compounds 

 in which the iron does not play the part of an ion, and in which, for 

 this reason, it cannot be directly demonstrated by the ordinary 

 reagents. How this ' masked ' iron can be best revealed is described 

 in the author's Physiological Histology, pp. 290-293. Ascoli 2 is of the 

 opinion that the iron does not fix on to the albumin at all, but to 

 the nucleic acid or to the para- or pseudo-nuclein of the nucleo- 

 albumin. Before the differences between salts and non-electrolytes 

 were understood, much was written about these compounds, and the 

 expression was used that iron, iodine, etc., were in 'organic union/ 

 and such iron-compounds as Bunge's haematogen 3 and Schmiedeberg's 

 ferratin 4 were supposed to be of great value to the animal organism, 

 for the latter was supposed to absorb iron only as ' organic iron ' 

 albumin, and not as an albuminate of iron or as an ordinary iron-salt. 

 The experiments of Gottlieb, 5 Yoit, 6 Kunkel, 7 Abderhalden, 8 and 

 others have shown this conception to be wrong, for the body is able 

 to absorb iron, as it does halogens, in the ionic state, and then 

 subsequently to de-ionise it. That, on the other hand, the body may 

 get rid of iron in the non-ionic state in the form of hemoglobin or 

 other iron-containing cell-constituents is also beyond doubt. Further 

 information as to how iron is bound up in the body is given in the 

 chapter dealing with the nucleo-proteids and with plasminic acid, see 

 p. 447. For the iron of haemoglobin see index. 



The compounds which albumins form with silver and with osmium 

 are mentioned on pp. 342, 343. 



1 H. Bechhold, Zeitschr. f. physiol. Cheat. 34. 122 (1901). 



2 A. Ascoli, ibid. 28. 246 (1899). 



3 G. Bunge, ibid. 9. 49 (1884). 



4 0. Schraiedeberg, Schmiedeberg's Arch. f. experiment. Patholog. und Pharmak. 33. 

 101 (1893). 



5 K. Gottlieb, Zeitschr. f. physiol. Chem. 15. 371 (1891). 

 c F. Voit, Zeitschr. f. Biol. 29. 325 (1892). 



7 A. Kunkel, Pfliigers Arch. f. die ges. Physiol. 61. 595 (1895). 



8 E. Abderhalden, Zeitschr. f. Biologie, 39. 113 (1899). 



