titration curves were obtained on samples that had been in contact with the solvent 1 to 2 hours. Hydroxysubstituted amides shoLved no evidence of 0-acetylation at room temperature. SUMMARY AND CONCLUSIONSThe titration of amides as bases is rapid and reproducible, and permits the determination of many compounds for which no direct methods exist. Adaptation of the method to visual titration procedures is not feasible a t present, because of lack of suitable indicators. Preliminary attempts to find satisfactory indicators for use in acetic anhydride were unsuccessful.Data obtained in this laboratory suggest the possibility of determining nniides and amines in mixtures. Total basicity is determined by titration in acetic anhydride. Amine acetylation is arrested by carrying out the reaction a t 0" C. (IO). Titration of the mixture in glacial acetic acid gives basicity due to amine. The difference represents amide content. ACKNOWLEDGMENTThe author wishes to thank Harold E. Zaugg for submitting many of the amides rcported in this paper. He also wishes to express his appreciation to G. Frederick Smith, Vniversity of Illlno's, for helpful discussion regarding the stability of perchloric acid-acetic anhydride mixtures.

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acetamide, studies of the former method (5) have shown that if 50 ml. of solution, 0.6VF in hydrochloric acid, which contains 500 mg. of arsenic(V) is heated almost to boiling, saturated with hydrogen sulfide, diluted to 100 ml. and cooled, resaturated with hydrogen sulfide, and heated to 100°C. in a pressure bottle, quantitative precipitation of the arsenic will require at least 30 minutes in the pressure bottle.By contrast it is calculated from the present study that in 100 ml. of solution, 0.3FF in hydrochloric acid and 0.5VF in thioacetamide, 500 mg. of arsenic(V) should be 99.9% reduced at 90°C. in approximately 1 minute and that sufficient hydrogen sulfide should be produced to precipitate the arsenic completely in about 6 minutes. (This

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