886 METABOLISM. 



In spite of the fact that it is the general experience of members of the 

 medical profession, that the administration of iron salts promotes the formation 

 of haemoglobin in certain forms of anaemia (chlorosis), there is no satisfactory 

 evidence that the administered iron enters into the formation of the newly- 

 formed haemoglobin, and it has even been denied that the alimentary canal is 

 capable of absorbing iron given in such form. The experiments of Kunkel, 1 

 however, show that if iron salts are administered to animals along with their 

 food, the blood, liver, spleen, and other organs exhibit an excess of iron over 

 that of control animals. Hall 2 also obtained distinct evidence of iron 

 absorption under like circumstances. When iron salts are injected sub- 

 cutaneously into a vein, most of the iron appears at once in the urine, some 

 is secreted into the intestine, 3 but somg is stored in the liver and is only 

 gradually eliminated. Experiments upon animals, in which the haematogens 

 of Bunge have been removed from the food and replaced by iron salts, have 

 been attempted, 4 but have presented serious difficulties. 5 Marfori, 6 however, 

 working with Schmiedeberg, obtained a large amount of absorption of iron 

 when given to dogs in artificial combination with albumin. Macallum also 

 has shown that iron, both in organic and inorganic combination, is absorbed 

 by the intestinal mucous membrane. 7 



Lime is taken in and assimilated by the organism, also in all probability 

 in the form of organic compounds, probably with proteids. 8 It occurs in 

 large amount in milk, but in most other forms of foodstuffs it is deficient 

 as compared with other constituents of the ash; the leguminosse 

 contain more than most foodstuffs. The only food which has the same 

 amount as milk is the yolk of egg, which should therefore always 

 be given to children when milk is either not procurable or cannot be 

 digested." 9 



The withholding of lime from the food of growing animals causes rickets ; 10 

 but rickets may occur in children, in spite of their food containing an adequate 

 amount of lime. 11 Probably, owing to abnormal conditions of nutrition, the 

 lime is under these circumstances not assimilated. 



In adult animals (pigeons), feeding with foods containing little or no lime 

 has been found eventually to cause alterations in the bones, which become 

 unusually brittle and thin (osteoporosis). 12 



1 Arch.f. d. ges. Physiol., Bonn, 1891, Bd. 1. S. 11; 1895, Bd. Ixi. S. 595. 



2 Arch. f. Physiol. , Leipzig, 1894, S. 456 ; and 1896, S. 49. 



3 Mayer, Diss., Dorpat, 1850, quoted by Bunge. Quincke (Arch.f. Anat., Physiol. u. 

 wissensch. Med., 1868, S. 150) failed to find it in an isolated portion of intestine with a 

 Thiry fistula, but Macallum (Journ. Physiol., Cambridge and London, 1894, vol. xvi. p. 

 268) obtained evidence of it in the crypts of Lieberkuhn. 



4 Socin, Ztschr. f. physiol. Chem., Strassburg, 1891, Bd. xv. S. 93 ; v. Hosslin, Ztschr. 

 f. Biol., Miinchen, 1882, Bd. xviii. S. 612 ; Hall, Arch.f. Physiol., Leipzig, 1896, S. 142. 



5 Consult upon the subject, Bunge, " Lehrbuch," 1894, 3te Aufgabe, S. 83 ; and Wool- 

 dridge's translation; also Neumeister, "Lehrbuch," Jena, 1897, 2te Aufl., S. 382 7 392, 

 where the subject is very fully treated and many more references to the literature will be 

 found. 



6 Arch. f. exper. Path. u. PharmaM., Leipzig, 1892, Bd. xxix. S. 212. 



7 Op. cit., 1894. 



8 Fokker, Arch.f. d. ges. Physiol., Bonn, 1873, Bd. vii. S. 274. 



9 Bunge, " Lectures," Wooldridge's translation, p. 111. 



10 J. Forster, Ztschr. f. Biol., Miinchen, 1873, Bd. ix. S. 369 ; and 1876, Bd. xii. S. 464 ; 

 E. Voit, ibid., 1880, Bd. xvi. S. 55 ; Baginsky, Arch. f. Physiol., Leipzig, 1881, S. 357 ; 

 and Virchow's Archiv, 1882, Bd. Ixxxvii/S. 301 ; Seem'ann, Ztschr. /. klin. Med., Berlin, 

 1882, Bd. v. S. 1 and 152. 



11 Riidel, Arch. f. exper. Path. u. PharmaJcoL, Leipzig, 1893, Bd. xxxiii. S. 90 ; 0. 

 Vierordt, Verhandl. d. xii. Cong. f. innere Med., Wiesbaden, 1893, S. 230. 



12 Chossat, Compt. rend. Acad. d. sc., Paris, 1842, tome xiv. p. 451 ; C. Voit, Ber. d. Vers. 

 d. Naturf. z. Miinchen, 1877, S. 243; Art. "Ernahrung" in Hermann's "Hanclbuch," 

 Bd. vi. S. 379 ; the earlier literature of the subject will be found in this article. 



