In the previous paper, it has been shown that, in order to explain the action of sucroclastic enzymes, it is necessary to assume not only that the enzyme combines with the hydrolyte but that it is also more or less affected by— and presumably combines with— the product of change. At present there is but little information available bearing on this latter contention. The experiments to be described have been made with the object of ascertaining by direct observation whether and to what extent the action of a given enzyme is affected by one or more of the products formed under its influence.