The auxins of 12 day old Vicia faba roots heve been studied. Avena internode and straight growth tests were Used to study auxins on paper chromatograms. Spectrophotofluorimetric methods were developed for the study of indoles and related compounds. A method of separating indoles on cellulose ion exchange compounds isdescribed. Other methods used to determine the chemical nature of the auxins isolated were, chemical determinations. uv. spectroscopy, solvent partition; paper chromatography and electrophoresis. An assessment of the sources of error in extraction, solvent partition and in elution from paper chromatograms was made. An attempt was made to locate IAA in the ether soluble fraction of extracts. Tryptophan and DOPA were identified in the water soluble fraction and quantitatively estimated by fluorimetry. The possible role of these compounds in auxin biogenesis is discussed. The amino acids, sugars, phenolic compounds and unknown yellow Ehrlich reactors in the water soluble fraction were studied. Water soluble material was treated on ion exchange cellulose columns to determine whether or not auxins might he released or retained, on the column during this treatment. Ehrlich reactors produced on the DEAE cellulose columns have been studied. Evidence for interconvertible auxins and. for a non-indolic auxin system is discussed. The correlation of Bioassay and fluorimetric analysis of auxins and work on the auxins in Cabbage extracts is described. IAN was identified by spectrophotofluorimetric techniques in the neutral ether fraction of Cabbage extracts.