A characteristic difference between guncotton and collodion cotton is the insolubility of the former in ether or alcohol or a mixture of these liquids.
It is not used itself in medicine owing to its insolubility in water and ether.
Its insolubility is much the same as keratin.
As an antiseptic salicylic acid is somewhat less powerful than carbolic acid, but its insolubility renders it unsuitable for general use.
It is a more powerful antiseptic than carbolic acid, but its insolubility prevents its being used for the same purposes.
They are characterized by their insolubility or very slight solubility in water; as examples may be mentioned erythrinic acid in Roccella and Lecanora; evernic acid in species of Evernia, Ramalina and Cladonia; lecanoric acid in Lecanora, Gyrophora.
They can be distinguished by their insolubility in cupramfnonia, which dissolves cellulose, and by their behaviour towards stains, some of which stain pectic substances but not cellulose.
Metastannic acid is distinguished from orthostannic acid by its insolubility in nitric and sulphuric acids.