ACTIONS OF IRON SALTS 255 



when iron salts are swallowed no such effects are produced, 

 for absorption is too slow and the quantity too small. 



It would thus appear that iron salts are absorbed, but 

 only partially and slowly from the alimentary tract ; only 

 small proportions of the doses prescribed can be used by the 

 red blood corpuscles ; the absorbed portions, as occur with 

 so many other metallic salts, accumulate in the liver, spleen, 

 bone marrow, and lymphatic glands, and are again returned 

 to the intestine to be excreted. 



The numerous salts of iron possess much the same kind of 

 action, but differ considerably in the degree of their activity. 

 Comparing the ferrous with the ferric salts, the latter are 

 darker coloured, more soluble and stable, as well as more 

 irritant and astringent. Small dogs are injured by 4 or 5 

 grains of ferric chloride, but swallow without harm 40 

 grains of ferrous sulphate. The more soluble ferric salts are 

 notably irritant, astringent, and corrosive. In the earlier 

 stages of convalescence, where the stomach is irritable, in 

 young patients, and especially in dogs, ferrous iodide or the 

 carbonate, in the conveniently keeping saccharated form, is 

 usually better borne than the ferric chloride, or even the 

 ferrous sulphate. But in order to secure the full tonic 

 effects of iron it is essential that the bowels be maintained 

 in a natural state, and an occasional laxative should be given 

 to counteract the constipating effect of the drug. Where 

 prompt astringent effects are to be produced, full doses of 

 the chloride or other soluble ferric salt are given. 



The salts of iron chiefly used in veterinary practice, and 

 hence demanding special notice, are the saccharated car- 

 bonate, ferrous sulphate, and iodide, with the ferric oxide 

 and chloride. 



Metallic iron, as filings or pulvis ferri, is occasionally given 

 in cases of poisoning with salts of mercury and copper. 

 Ferrum redactum, or reduced iron, is a greyish-black powder, 

 containing 75 per cent, of metallic iron with iron oxide. 

 Tasteless, and without astringency, it is frequently pre- 

 scribed for young, unthrifty animals as a hsematinic, which 

 is less apt to derange digestion than the sulphate. Iron 

 arsenate has been prescribed in squamous and herpetic skin 

 diseases, in about the same doses as arsenic, and is also 



