COPPER SALTS AS DISINFECTANTS 139 
Chloramine. Toluenc parasulfondichloramin is formed when nascent 
chlorine formed in aqueous solutions of hypochlorite is brought in 
contact with suppurating wounds. Dakin (1916, 1917) has proposed 
the name dichloramine-T for this compound. He has shown that 
most of the substances containing a NCI group are strongly germicidal. 
The presence of more than one such groups does not seem to increase 
the germicidal properties to any marked degree. It may be used in 
stronger concentrations than with some of the other disinfectants. It 
is claimed that its use is as simple as the use of tincture of iodine. 
Zinc Chloride. This compound had quite a reputation as a disin- 
fectant at one time, but recent knowledge has caused the compound 
to fall into disuse. McClintic (1905) found that B. cold was not killed 
in one hour’s exposure to a 5 per cent solution and that it required ten 
minutes for a 25 per .ent solution to kill the same organism. The 
spores of B. subtilzs and B. anthracis were found to resist 100 per cent 
and 50 per cent solutions for 30 and 40 days respectively. 
Copper Salts. These have been used in the treatment of public 
water supplies but not generally in ordinary disinfection. Kellerman 
and Beckwith (1906) have given a résumé of the literature up to the 
time when their paper was published. Moore and Kellerman (1905) 
reviewed the application of copper sulphate to water sterilization and 
the removal of alge. About 10 lbs. per million gallons of water were 
sufficient. Its toxic properties are said to be due to the copper salts 
which are formed with proteins. Embrey (1912) reported that copper 
sulphate would destroy alge in a dilution of 1 to 3 million. DeWitt and 
Sherman (1916) studied the effects of both copper sulphate and cupric 
chloride on bacteria. Their results showed that copper was not a 
rcliable disinfectant. They state that 2.5 parts of cupric chloride 
and 4 parts of copper sulphate per million would kill B. colz and 
B. typhi. 
Ferrous Sulphate, FeSO4. This has little germicidal value unless 
in solutions of over 2 per cent. When it is present above 5 per cent, 
it will restrain development of putrefactive changes. McLaughlin 
(1903) secured no disinfection in applying it in saturated solution to 
feces. 
Boric Acid, H3BO3. Boric acid is a mild disinfectant and is used 
in 5 to 100 per cent solution. It is of especial value for use on mucous 
membranes such as those of the eye and the nose. Ochsner (1916) 
stated that boric acid does not destroy pathogenic bacteria but does 
diminish their virulence. Wet dressings of boric acid were much more 
effective on the pyogenic cocci than on other infections. 
