Abstract
For Pt. I see Ibid., vol.5, 1830 of 1972. In this article the study of the effects of nonmagnetic impurities on the critical properties of the Ising model is continued. Two separate aspects of the problem are considered. The behaviour of the susceptibility as the impurity concentration changes at constant temperature is investigated using expansions in terms of the concentration variable. The high temperature series expansions for the fourth field derivative of the free energy are also studied in order to determine whether its singularity occurs at the same temperature as that of the susceptibility. The problems of extracting meaningful results from the series analysis are discussed.