INORGANIC FOODS. 389 



been any poisoning observed from taking iron salts, provided the doses and 

 the manner in which they are introduced are so chosen that large amounts 

 of iron do not get into the circulation by erosion of the alimentary 

 canal. Little by little the view became accepted that iron and the 

 heavy metals find their principal place of elimination not in the kid- 

 neys, but in the intestines. It is true that a part of the iron leaves the 

 body through the urine, for the latter invariably contains small amounts 

 of iron. The amount, however, is very slight, and is not materially 

 increased when iron is taken as medicine. Long ago it was suggested 

 that probably a large part of the iron was eliminated through the intes- 

 tines, and was, therefore, to be found in the faeces. The fact that after 

 taking iron into the system, the most of it did actually appear in the faeces, 

 led to the erroneous conception that no absorption took place. It has 

 been shown in the first place that subcutaneous and intravenous injection 

 of iron salts always result in a part of the iron being eliminated through 

 the intestines. 1 On the other hand, it may be said that this does not rep- 

 resent a normal condition. It was indeed conceivable that the organism 

 seeks to get rid of the iron salts poisonous to it as quickly as possible by 

 all the means available. The credit of having done the most towards 

 explaining the absorption and elimination of iron salts belongs chiefly to 

 Kunkel, Quincke, and Hochhaus. 2 These investigators made use of 

 ammonium sulphide as a reagent for tracing the course of iron in the 

 tissues; 3 in some cases, potassium ferrocyanide was used as well. If, for 

 example, mice are fed for a long time upon milk which, as we have seen, 

 contains but little iron, then, on placing the alimentary canal of these 

 animals in ammonia and ammonium sulphide, the iron test does not 

 appear, or at most there is only a slight green coloration. 4 The same is 

 true of the other organs of mice, after they have subsisted upon milk 

 alone for a considerable period. The best tests for iron are given by the 



1 Hamburger: Z. physiol. Chem. 2, 191 (1878-79); Lapicque: Arch. Physiol. normale 

 et pathol. 1895. 



2 Kunkel: Pfliiger's Arch. 50, 1 (1891); 61, 595 (1895). Filippi: Arch. exp. Path. 

 Pharm. 34, 462 (1895). Hochhaus u. Quincke: ibid. 37, 159 (1896). Quincke: ibid. 

 37, 183 (1896). W. F. C. Weltering: Z. physiol. Chem. 21, 190 (1895-96), and Over de 

 resorptie van ijrerzonten in het spysverteringskanaal, Utrecht, 1895. W. S. Hall: 

 Arch. Anat. Physiol. 1896, 49 ; 1894, 455. A. Macallum : J. Physiol. 1894, 186. Abder- 

 halden: Z. Biol. 39, 113 (1899). A. Hofmann: Virchow's Arch. 151, 484 (1900). G. 

 Swirski: Pfliiger's Arch. 17, 466 (1899). Tartakowsky: ibid. 100, 586 (1903). Hubert 

 Sattler: Ueber Eisenresorption u. Ausscheidung im Darmkanal bei Hunden u. Katzen 

 Inaug. Diss. Kiel, 1904, and Arch, exper. Path. Pharm. 52, 326 (1905). Franz Miiller: 

 Deut. med. Wochschr. No. 51 (1900) and Deut. Med.-Ztg. No. 30 (1901). Virchow's 

 Arch. path. Anat. klin. Med. 164, 436 (1901). 



3 Cf. R. Gottlieb: Z. physiol. Chem. 15, 371 (1891). 



4 A. Mayer was the first to apply this method (Dorpat, 1850). Later, Perls (Vir- 

 chow's Arch. 39, 42 (1867)) made use of K 4 Fe(CN) 6 . 



