The product or “bake” appears as a hard grayish mass, slightly porous. It is dug out, pulverized, boiled up in a large evaporating dish, containing water and a little (10cc.) hydrochloric acid, with animal charcoal and filtered. The solution should be almost colorless. The effect of the slight amount of hydrochloric acid was accidental; the first solutions were always a deep red color due to some of the red dyestuff seeming to be present, and the longer the solution was boiled the redder it got. A little acid seems to prevent this entirely. The solution is evaporated on a water bath until a scum has formed on the surface when it is allowed to cool and crystallize. It crystallizes in small almost white needles, which appear to fill the entire liquid; this is deceptive as on filtering the bulk is considerably reduced. They fall to a powder when they are dry. If they are colored red or pink they are washed while still on the filter with water; alcohol does not remove this color. The acid as formed has no melting point, but chars and decomposes on heating. A sample was tested for nitrogen and sulphur with very good positive results. On fusion with caustic soda and acidification of the product a positive reaction was obtained on the addition of bromine water as is customary with phenols. It was identified as identical with the acid of Nevile and Winther (loc. cit.) by conversion thru the diazo compound into dinitro ortho cresol, melting at 85.8 as described under the description of the diazo compound. SULPHONATION OF PARA TOLUIDINE Metcalf, (loc. cit.), gives a method for the preparation of the sulphonic acids of para toluidine, and states that both the possible acids are formed, with the meta position (referred to the methyl group) in good yield. Schultz and Julius, (“Farbestoff Tabellen”, 1894 Edition, Trans, by F. C. Green), and Nevile and Winther, (loc. cit.), say that the sulphonation of para toluidine gives a mixture of the sulphonic acids, with the ortho (referred to the methyl group) sulphonic acid in a much greater yield. As the sulphonation of para nitro toluene gives (Dissertation, R. S. Norris, BPL. 5976.109) a ninety-five per cent yield of the ortho sulphonic acid, it would seem as though the amino compound should give a large yield of the acid (sulphonic acid group ortho to the methyl group,) and such was found to be the case.