While log P appears to be the sole determinant of log T, some theoretical studies indicate that there is a definite 'steric basis of hydrophobicity' because the dominant source of energy for hydrophobic interactions of solute in water depends on molecular shape and size. Moreover, some recent studies, where log P is highly correlated with V(w) and topological indices, provide further evidence for the geometrical/topological basis of hydrophobic behavior. This may be the reasons for the excellent correlation of log T with V(w) and other topological steric parameters. The dependence of lipophilicity of the barbiturates upon molecular shape and size is evident from the correlation of log P.