This silver-gelatin colloid (MW = undefined), prepared by a proprietary process, in which silver nitrate, sodium hydroxide, and gelatin are combined, inhibits the erosive growth of Neisseria gonorrhoeae introduced into a neonate’s eyes during passage through an infected birth canal. The preparation was perfected and commercialized by Philadelphia physician, Albert Coombs Barnes, who used the proceeds to amass one of the finest private collections of Impressionist paintings, now comprising the world- famous Barnes Collection. Note: Despite claims to the contrary, some micoorganisms manage to resist silver toxicity by expressing ATP- dependent cation pumps that export Ag+ .