Determination of lactose alone and in the presence of sucrose by the method of Munson and Walker.

The existence of uncertainties in the tables employed in the determination of lactose, alone and in the presence of sucrose, by the method of Munson and Walker has led to the redetermination of the reducing-sugar values from which these tables were calculated. The original tables were based on the weights of cuprous oxide corresponding to various weights of lactose, and in the present paper all values are referred to the weights of copper determined * electrolytically. Data showing the magnitude of the contamination of the cuprous oxide under the conditions prevailing in the method are given. The table of Straughn and Given for mixtures of lactose and sucrose in the ratio of 1:12 is shown to be in error. From the redetermined values an extensive table of the copper values for lactose and for two ratios of lactose and sucrose has been computed.