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A proportion of the copper sulfate and alkaline tartrate of Fehling solution, Soxhlet modification, has been found which gives no black precipitate on heating, a minimum blank, and a negligible autoreduction.Study of the effect of time and temperature of heating on the copper number shows in all cases an increase in copper number until heating has been continued for 30 minutes, and after that a constant value.Rag pulp heated with Fehling solution for 30 minutes at 100°C. and 2 hours at 75°C. gives a copper number corresponding to the lower

first observation of a reaction between cellulose and phenylhydrazine appears to have been made in 1892 by Nastjukoff,2 who found that when cellulose was treated with phenylhydrazine hydrochloride in the presence of sodium acetate, it took up phenylhydrazine and assumed a yellow color which could not be extracted with alcohol or ether. The reaction was subsequently investigated by Vignon.3 Finally it was the subject of experimentation by Knecht, who attempted to use the reaction in the estimation of the degradation of cellulose by the so-called "osazon method."4 The procedure employed by Knecht was the

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