The leaves of a closely allied plant, Empleurum serratulum, are employed as a substitute or adulterant for buchu.
Tartaric acid, which is sometimes present in large quantities as an adulterant in commercial citric acid, may be detected in the presence of the latter, by the production of a precipitate of acid potassium tartrate when potassium acetate is added to a cold solution.
It may be skimmed off the underlye and placed direct in the frames for solidification; but that is a practice scarcely at all followed, the addition of resin soap in the pan and the subsequent " crutching in " of silicate of soda and adulterant mixings being features common to the manufacture.
On this adulterant Sir Thomas Wardle remarks " With a solution of sugar, silk can have its weight augmented from I oz.
Now, intentional adulteration is practically non-existent, chiefly because of the fact that in the places of production the price obtainable is so low that any possible adulterant would be too costly to collect.