Such substances are silver nitrate (lunar caustic), the caustic alkalis (potassium and sodium hydrates), zinc chloride, an acid solution of mercuric nitrate, and pure carbolic acid.
Against the bacteria quinine is not at all an exceptionally powerful antiseptic, though more powerful than carbolic acid.
These all resemble carbolic acid more or less closely, and may be described as general protoplasm poisons.
Do not give them carbonated water as this has carbolic acid which rots teeth.
In early inquiries a great point was made of the prevention of putrefaction, and work was done in the way of finding how much of an agent must be added to a given solution, in order that the bacteria accidentally present might not develop. But for various reasons this was an inexact method, and to-day an antiseptic is judged by its effects on pure cultures of definite pathogenic microbes, and on their vegetative and spore forms. Their standardization has been effected in many instances, and a water solution of carbolic acid of a certain fixed 'strength is now taken as the standard with which other antiseptics are compared.