ARGYROL 143 



with a proteid substance obtained from wheat. It occurs as a brownish 

 powder, soluble in less than its own weight of water, forming dark-brown 

 solutions which stain clothing black, but the stains may be removed by a 

 1 : 500 solution of corrosive sublimate. Like protargol, it is not precipi- 

 tated by the salts of the tissues, nor does it coagulate albumin, so that its 

 action is not neutralized by the tissues — as is the case with silver nitrate ; 

 and thus, unlike the latter, it possesses a penetrating power when applied 

 locally. Argyrol is used in from 5 to 50 per cent, aqueous solution for 

 the same purposes to which protargol is adapted. Solutions of argyrol 

 should be freshly made. Argyrol is the most valuable silver substitute we 

 have and so far from being irritating is actually sedative in 10 per cent, 

 solution. In inflammatory diseases of the mucous membranes of the nose, 

 throat, eye, urethra and bladder it has no equal. On account of its 

 markedly irritating properties, silver nitrate has been largely replaced by 

 argyrol and protargol. But neither are antiseptics in any degree, when 

 compared to silver nitrate, and it is impossible to wholly explain their 

 beneficial effects. The percentage of silver in the organic silver com- 

 pounds does not indicate their antiseptic value (Marshall & Neave). 



Soluble Silver. (Non-official.) 



Soluble silver, known also as Colloidal Silver, or more commonly as 

 Collargol, is an allotropic form of metallic silver (87 per cent, silver) 

 wholly soluble in water, and discovered by Lea about 1890. It may be 

 used intravenously, subcutaneously, by inunction (as Crede's ointment, 

 see below), and by the mouth, if first dissolved in the proportion of five 

 parts of collargol with one part of white of egg in one hundred parts of 

 water; or it may be given in pill with sugar of milk. Collargol has been 

 given in the past intravenously in all kinds of infections for its supposed 

 antiseptic action but it has not proved successful and has dropped into 

 disuse. The dose intravenously is 3ss-i (2-4) for horses; dogs, gr.i-ii 

 (.06-0.12), given in 2 to 5 per cent, aqueous solution. Collargol has been 

 given also by the rectum (H., 3i-ii, in Oi water; D., gr.ii-iv in §ii-iii 

 water). 



Crede's Ointment, made by incorporating collargol with lard and wax 

 to the extent of 16 per cent., has given good results when rubbed for 

 thirty minutes into the skin (which has previously been scrubbed with 

 soap, water and alcohol) in the treatment of local and even general 

 infections. It often arrests the formation of boils, threatened suppura- 

 tion of glands, lymphangitis, phlebitis, cellulitis and mastitis. The dose 

 by inunction is % to 1 ounce for horses, % to 1 dram for dogs. Collargol 

 appears to be non-toxic when given intravenously or by inunction, if used 

 with reasonable care. 



Zincum. 



(Zinc is not used in Medicine in the metallic state.) 

 ZiNci Chlokidum. Zinc Chloride. ZnCU. (U. S. & B. P.) 

 Synonym. — Chlorure de zinc, Fr. ; zinkchlorid, chlorzink, G. ; zincum chlo- 

 ratum, P. G. 



Derivation. — Dissolve zinc in hydrochloric acid by boiling. The solution con- 

 tains the zinc chloride with chlorides of iron and lead as impurities. These are 



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