366 COLLOIDS IN BIOLOGY AND MEDICINE 



scientific foundation by TH. PAUL. He demonstrated that colloidal 

 preparations of silver split off silver ions in aqueous solution and in 

 such quantity that the blood is saturated with silver ions because it 

 can take up very few of them by reason of the NaCl it contains. In 

 these investigations the interesting fact was disclosed that the various 

 colloidal silver preparation behaved differently when diluted in aqueous 

 solution. The Ag ion concentration diminished when protargol is di- 

 luted, it remains constant with sophol and increases with lysargin and 

 collar gol. This explains the difference in their therapeutic application. 

 The remarkable fact that the concentration of Ag ions increases with 

 dilution is paralleled in complex substances as well as in mixtures of 

 the weaker acids and their salts (increase of H ion concentration). 

 According to O. Goos the action of silver nitrate and silver iodid is 

 to be attributed to the silver ions and complex compounds. 



Heretofore colloidal metals and their compounds were employed 

 solely in aqueous solutions; recently, however, metal organosols have 

 achieved therapeutic recognition. Employing lanolin as a protective 

 colloid, C. AMBERGER has prepared many colloidal metal solutions. 

 We have interesting publications concerning lanolin solutions of 

 palladium hydroxyd sol (trademarked leptynoT). M. KAUFFMANN 

 employed it successfully in obesity cures. It acts as a carrier of 

 hydrogen, increasing oxidative processes which are deficient in the 

 obese. Certain psychoses which may be traced to similar causes 

 seem also at times to be favorably influenced (W. GOM). 



Silver hydrosol of all the metal hydrosols has been the most carefully 

 studied; the other hydrosols show great variations in some respects. 



According to G. IzAR,* 3 even the Macedonians covered wounds 

 with silver plates, and in parts of Italy erysipelas is still treated in 

 the same way. In the United States, silver foil is employed in some 

 hospitals to seal open wounds (R. HUNT, Washington). CREDE at 

 first employed CAREY LEA'S colloidal silver. Manufacturers soon 

 began to make colloidal silver preparations which are sold under a 

 great variety of names. Among the best known are Argentum Col- 

 loidale Crede, which is sold as Collargol (von Heyden). It is pre- 

 pared by the reduction of silver nitrate with ferric citrate; a dextrin 

 probably serves as the protective colloid. In the case of Lysargin 

 (Kalle) a sodium lysalbinate serves as protective colloid. Electrar- 

 gol and Argoferment are made by electric pulverization in the presence 

 of a stabilizer (probably gelatin). According to J. VOIGT the linear 

 diameter of the particles in various commercial preparations varies 

 between 14 and 26 MJL. 



M. ASCOLI and G. IZAR prepare their hydrosols according to the 

 method of G. BREDIG (pulverization of silver, gold or platinum elec- 



