SILVER SALTS AS DISINFECTANTS 135 
Biasiotti (1910) reported that colloidal silver electrically prepared 
would kill Staphylococcus pyogenes aureus, B. typhi, and Bacterium 
diphtherie in a few hours. The silver is probably united to the proto- 
plasm in some way because Gram positive bacteria are made Gram 
negative. Simpson and Hewlett (1914) experimented with colloidal 
silver in the form of “collosol”’ on the typhoid bacillus and found it 
an active bactericide. The “ collasols’’ are said to be non-poisonous 
but slow of action and very expensive. 
Silver is combined with several substances which have wide appli- 
cation in certain phases of the disinfection problem. Argyrol is the 
silver salt of vitellin and is used in solutions of from 1 to 4 per thousand. 
Protargol is a compound of silver with protein. It contains 8 per cent 
of silver nitrate. Albargin is a silver salt of galactose. It may be used 
on mucous membranes, which explains its use in the venereal diseases. 
It contains about 10 to 15 per cent of silver. Often it is applied as 
10 to 20 per cent solutions in 20 per cent glycerol. Argentamin, a 10 
per cent solution of silver nitrate in 10 per cent ethylene-diamin, has 
much use in gonorrheal infections. It is usually diluted to about 1 
part in 300. Argentose is a silver compound of nucleoprotein and is 
used like silver nitrate. Argonin, a silver caseinate, is used in a 3 per 
cent solution for treatment of gonorrhea and ophthalmia neonatorum. 
Silver Nitrate, AgNO3. This is a common silver disinfectant. It 
is not as powerful as mercuric chloride but does not precipitate proteins 
as does mercuric chloride. 
Silver Citrate, Ags;C,.H;0;7. This is used as a wash for wounds and 
for gonorrhea in dilutions of about 0.25 per cent. Great precautions 
must be used to obtain fresh solutions. It is also known as i7rol. 
Silver Lactate. This compound of silver is used as a mild disin- 
. fectant. It has about the same applications as has silver citrate. 
Bismuth Compounds. Bismuth subiodide, bismuth subsalicylate, 
bismuth nitrate are all used as weak disinfectants. They are used in 
solutions of 1 to 1000 to 1 to 4000 and are probably not very reliable. 
Calcium Compounds. Chloride of Lime. This is also known 
under the names of bleach, hypo and bleaching powder. It has attained 
an important position in sanitation probably for two reasons; it pos- 
sesses great bactericidal properties and may be secured for a low price. 
Thus it satisfies two of the characteristics of a good disinfectant. In 
the dry condition chloride of lime is calcium oxychloride which, in 
the presence of water takes on another atom of oxygen. 
2CaOClz = Ca(OCl)2 
