By inorganic ferments is understood finely-divided metals (platinum, silver, gold, etc.) suspended in water as solutions. This fine division of the metal is obtained by passing a strong electric current from one bar of metal to another in pure water. It does not concern true solutions, however, because there is no change in the freezing-point, the vapor-tension, or the boiling-point of the fluid; neither does it not produce any osmotic pressure. For these reasons these mixtures are called pseudo-solutions or colloidal solutions; they are analogous to solutions of starch and albumin, but have also remarkable fermentative properties. Thus, a colloidal solution of platinum hastens the oxidation of alcohol into acetic acid; others invert cane sugar, etc. Like organic ferments, small amounts of colloidal solutions of metals effect large transformations without themselves undergoing any change. Such reactions are termed catalytic.
The work here referred to has been carried out by Bredig