TOXICOLOGY AND PHARMACOLOGY 383 



salts are powerful poisons to algae, infusoria and fungi. According to 

 BOKORNY they are effective even in dilutions of 1 : 100,000,000. 

 Vertebrates can stand them in relatively higher doses; but even 

 among these there is considerable variation; cats, for instance, are 

 said to be very sensitive to copper salts. 



Some of the heavy metal cations in spite of always precipitating al- 

 bumin appear to be able to enter the circulation and to be definitely 

 stopped only when they reach the filter membranes of the glands (liver, 

 spleen, kidneys). On this account we frequently encounter kidney 

 irritation from the toxic heavy metal cations (mercury, lead, etc.). 

 Doubtless their solubilities in the lipoids are an important factor. 



The formation of irreversible albumin compounds kills the cell 

 which is involved. [Hg, when absorbed to the extent of 4 mg. per 

 kilo, slays relentlessly. It forms an irreversible compound, unaffected 

 by antidotes or by washing with water as has been shown by SANSUM. 

 Tr.] On this account besides the acids and the alkalis, salts of the 

 heavy metals, e.g., copper sulphate, silver nitrate and zinc chlorid, are 

 used as caustics. Astringents act by causing a coagulation of the 

 topmost layers of mucous membranes or inflamed surfaces. There- 

 fore they include salts of the heavy metals, as silver nitrate, copper sul- 

 phate and acetate, zinc sulphate and acetate and bismuth subnitrate. 

 Besides these, ferric chlorid and the various aluminium salts (alumin- 

 ium acetate, alum, etc.) of whose powerful flocculating action, resulting 

 from the trivalence of Fe and Al we have already learned (see p. 84) ; 

 the flocculating action in fact depends on the colloidal ferric hydroxid 

 and aluminium hydroxid contained (see below). Similar results may 

 be obtained with tannin, formaldehyd, and in short from all the hard- 

 ening agents discussed in Chapter XXIII, provided their employment is 

 not precluded by undesirable properties (e.g., picric acid and osmic acid). 



Iron Salts and Iron Oxid Hydrosol. 



Recent researches have shown that only ionizable iron compounds 

 have a pharmacologic action (upon the formation of red blood cor- 

 puscles in chlorosis), but they show, 1 on the contrary, that prepara- 

 tions with iron firmly bound (hemoglobin preparations hi particular) 

 have no specific action. The numerous preparations in which iron is 

 administered as a colloidal iron oxid (ferri oxidat. saccharatwn solu- 

 bile, liq. ferri oxid. dialys, and in some of the chalybeate mineral 



1 It may be mentioned in contradiction to this, that colloidal Fe(OH) 3 , ac- 

 cording to M. ASCOLI and G. IZAR, favors the total autolysis of the liver as well as 

 its individual factors (see p. 369 et seq.) and that the ferments taking part in the 

 formation of uric acid are activated by the addition of colloidal ferric hydroxid; 

 larger quantities, however, inhibit uric acid formation. 



