Gordon & Turner (1955) reported that glucose and other sugars intensify the protective action of glycine against the heat-inactivation of complement, so that in their presence the concentration of glycine required to protect complement against inactivation at 55° C. is greatly reduced. Moreover, when high concentrations of glycine (e.g. 10%) were used, higher temperatures were required to inactivate complement if the glycine was dissolved in a high concentration of a sugar. They also showed that although this intensification is a property of a wide range of sugars, it is not shown by the corresponding alcohols, although inositol is exceptional in causing marked intensification. No explanation was offered for these findings and further experiments have been undertaken to throw light on them.