In 1897 he reported some significant conceptual and methodological advances in his study of variation. "I have argued that variations of a discontinuous nature may play a prepondering part in the constitution of a new species." He attempts to silence his critics (the "biometricians") who misconstrue his definition of discontinuity of variation by clarification of his terms: "a variation is discontinuous if, when all the individuals of a population are breeding freely together, there is not simple regression to one mean form, but a sensible preponderance of the variety over the intermediates… The essential feature of a discontinuous variation is therefore that, be the cause what it may, there is not complete blending between variety and type. The variety persists and is not “swamped by intercrossing”. But critically, he begins to report a series of breeding experiments, conducted by Edith Saunders, using the alpine brassica "Biscutella laevigata" in the Cambridge botanic gardens. In the wild, hairy and smooth forms of otherwise identical plants are seen together. They intercrossed the forms experimentally, “When therefore the well-grown mongrel plants are examined, they present just the same appearance of discontinuity which the wild plants at the Tosa Falls do. This discontinuity is, therefore, the outward sign of the fact that in heredity the two characters of smoothness and hairiness do not completely blend, and the offspring do not regress to one mean form, but to two distinct forms.”