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is., just before the end-point the indicator is in combination with the anion-active agent and out of direct contact with the added aqueous titrant. To liberate the methylene blue into the aqucous phase a certain minimum concentration OF cation-active substance must be established in the solvent phase by partition from thc aqueous phase which may conceivably require an addition of titrant in considerable excess of stoichiornetric proportions.A consideration of the individual compounds in Table V shows that the slightly high results obtained by titration with bromophenol blue as indicator may in practically every instance be explained by the presence OF some extraneous impurity such as sulphonic acids in the sodium oleyl sulphate and sodium oleate in the sodium oleyl-p-anisidide sulphonate and illustrates the extreme difficulty of preparing amphipathic substances OF absolute purity by ordinary crystallization methods. Conclusions(I) The solubility in organic solvents OF complexes formed between anion-active agents and methylene blue and between cation-active agents and bromophenol blue respectively form the basis of new partition-end-points in the titration OF anionactive with cation-active agents.(2) Procedures are described which enable such titrations to be conducted with greater precision that heretofore.(3) A study OF several purified anion-active agents indicates that virtually stoichiometric results are obtained by the new method on titrating one anion-active agent against another via an intermediate cation-active agent, irrespecure of whether methylene blue or bromophenol blue be used as indicator.(4) The end-point is more readily determined with bromophenol blue than with methylene blue.(5) Thc interpretation of results of titrations of various technical amon-active agents against a highly purified cation-active agent is complicated by the probable presence in these technical products of small proportions of by-products which also titrate with the cation-active agent, e.g., sodium alkyl sulphonates in sodium alkyl sulphates; sodium oleate in sodium oleyl-panisidide sdphonate. It is therefore impossible to state with absolute certainty that, by this method, cation-active agents titrate stoichiometrically with anion-active agents. Using bromophenol blue the relationship is approximately stoichiometric whereas with methylene blue a definite excess of cationactive agent is present at the end-point.(6) A possible explanation is advanced for the higher results obtained with methylene blue.(7) It does not follow that all anion-active or cation-active compounds are suitable for titration by the new method. Thus dodecyltriethylammonium bromide, used as a standard titrant in Table I gave low results for all anion-active compounds tested.(8) The mcthod has proved easy and accurate in the hands of unskilled operators. It is of particular value in following changes in active-agent concentrations, e.g., in studies of absorption by textile fibres, and in the control of continuous processing operations. Imperial Chemical...

The infrared absorptions of 141 analogues of griseofulvin and isogriseofulvin have been examined, and the behaviour of absorption bands associated with carbonyl, alkyl, alkoxy-, alkylthio-, and halogen substituents is described. Absorption bands that can be used to distinguish between 4'-oxo-2'-enol ether and 2'-0xo-4'-enol ether analogues, and between griseofulvin and epigriseofulvin, are reported. Certain analogies with the spectra of l-methoxycholest-l-en-3-one and 3-methoxycholest-2-en-l-one are discussed.

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