In other communications from this laboratory the normal diastase values1and the significance of elevated blood diastase2were discussed. The accurate assay of subnormal amounts of diastase afforded by the Somogyi technic3revealed that subnormal diastase values were far more frequent than were increased values. In preliminary reports4it was pointed out that low blood diastase values seemed to be indicative of impaired hepatic function. Analysis of the considerable material that we have accumulated, which forms the basis of this study, supports this early interpretation. Other investigators using the Somogyi technic have corroborated this concept.5 We are unable as yet to offer any valid explanation of the decrease in blood diastase associated with impaired hepatic function. If diastase were found in the liver, one could assume that the production of the enzyme is one of the functions impaired when the liver is affected. But, as