886 METABOLISM. 
In spite of the fact that it is the general experience of memhers 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 - 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 some 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. Macalhmi 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. gcs. Physiol., Bonn, 1891, Bd. 1. S. 11; 1895, Bd. lxi. S. 595. 
2 Arcli.f. Physiol., Leipzig, 1894, S. 456 ; and 1S96, S. 49. 
3 Mayer, Diss., Dorpat, 1850, quoted by Bunge. Quincke {Arch. f. Anat., Physiol, u. 
urissensch. Med., 1868, S. 150) failed to find it in an isolated portion of intestine -with a 
Thiry fistula, but Macallum (Joum. Physiol., Cambridge and London, 1894, vol. xvi. p. 
26S) obtained evidence of it in the crypts of Lieberkuhn. 
4 Socin, Ztschr. f. physiol. Chcm., Strassburg, 1891, Bd. xv. S. 93; v. Hbsslin, Ztschr. 
f. Biol., Miincben,'lS82, 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. 382-392, 
where the subject is very fully treated and many more references to the literature will be 
found. 
6 Arch. f. e.rper. Path. u. Pharmakol., 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. Yoit, ibid., 1880, Bd. xvi. S. 55 ; Baginsky, Arch. f. Physiol., Leipzig, 1881, S. 357 ; 
and Virchow's Archiv, 1882, Bd. lxxxvii. S. 301 ; Seem'ann, Ztschr. f. klin. Med., Berlin, 
1882, Bd. v. S. 1 and 152. 
11 Rtidel, Arch. f. exper. Path. v. Pharmakol., Leipzig, 1893, Bd. xxxiii. S. 90; O. 
Yierordt, Verhandl. d. xii. Cong. f. innerc Med., Wiesbaden, 1893, S. 230. 
12 Chossat, Compt. rend. Acad. d. sc, Paris, 1842, tome xiv. p. 451 ; C. Yoit, Ber. d. Vers. 
d. Naturf. z. Miinchen, 1877, S. 243; Art. "Ernahrung" in Hermann's "Handbuch," 
Bd. vi. S. 379 ; the earlier literature of the subject will be found in this article. 
