Quantitative paper chromatography has developed by ways that are totally different from those followed in chemical or classical analytical procedures. Entirely original means have been employed. On a microgramme scale and even for amounts that sometimes are a thousand times less, the results accomplished are of astounding simplicity and remarkably reproducible. This technique has all the character of a microtechnique. When perfected it is of general application: theoretical and practical; organic, inorganic; preparative or synthetic; analytical, qualitative, quantitative. This instance demonstrates the necessity of enlarging the microchemical concept beyond that of the notion of microanalysis and analysis.