Summary These results tend to show that a particular method of mechanical agitation of ice cream mixes reduces their viscosity by a partial splitting of fat clumps, to a constant low viscosity, attainable under the conditions of agitation, but the size of clumps and the viscosity can be reduced still further by more vigorous mechanical treatment as when the mix is subsequently run through the homogenizer at low pressure. The presence of clumps in ice cream mixes which have been agitated for basic viscosity determinations is a point which has apparently not been given serious consideration. Different conditions of agitation may vary in their effectiveness in splitting clumps and introduce a variable factor in the magnitude of the basic viscosity secured. Basic viscosity, as the term is now used for ice cream mixes, applies to a value secured under specified conditions and it is not a correct minimum value from the viewpoint of the lowest viscosity that might be present without fat clusters.