It is as though one should take a spoonful of black pepper and a spoonful of white salt, and thoroughly mix them. A drab "pepper-and-salt" mixture will result. But neither pepper nor salt will have changed its colour or its properties one iota. Could they be separated out again, each would be precisely as it had been before mixing. So it is with the Dominant and the Recessive traits in living organisms. They commingle intimately, but each retains its original and intrinsic quality. All the diverse and beautiful varieties of vegetation and the loveliness of flowers, in form and colour, result from multiple associations in hybrid-plants, of those which are known as the "Contrasted Traits" of parent-stock. III The lay reader need not perplex himself with the problems and phenomena of Mendelism. All he requires to remember are its three leading principles. Firstly, that in the world of Life, plant and animal, living attributes are divided into two contrasting orders. Secondly, that of these two orders of so-called "Contrasted Traits" ("Contrasting Traits" would be a fitter phrase), the two groups are as absolute and opposite in character and in significance as are the _plus_ and the _minus_ signs of Algebra, the Positive and the Negative potentials of Electricity, the conditions of Light and Darkness, of Blackness and Whiteness, of Heat and Cold. Thirdly, that the Dominant order of traits are paramount over and extinguish the Recessive order of traits. To sustain her equilibrium by a counterpoise of dual and contrary factors, physical and vital, Nature must preserve these factors absolute and unchangeable as the constitution and the opposite attraction of The Poles. But in order to produce her countless progressive variations of form and attribute, physical and vital, she assembles these contrary factors in countless progressively complex combinations, co-operations and correlations. It is conceivable, therefore, that the infinite gradations and variations of form and attribute found in the world of living creatures are, as in the world of plants, phenomena of the ever further differentiation and more complex combination, in the hybrid offspring of two parents, of two orders of Contrasting Traits, transmitted by the respective parents. In all their multiple associations and diverse developments, however, the two Sets of Traits remain unchanged, precisely as do the individual elements of chemical combinations. Variations in species result, accordingly, not from change in the essential traits, but from changes in the modes and the degrees of the commingling of these in organisms; and in the modes and degrees of their ever more complex associations in such.