Often the contradiction is merely the result of the imperfect theoretical conceptions of its discoverer, as we have already shown in regard to Nägeli. Bulman, too, fancies he has proved that bees do not distinguish between the different varieties of a flower, but visit them indiscriminately with the same eagerness, thus causing intercrossing of all the varieties, and preventing any one from becoming dominant. But are the varieties which we plant side by side in our gardens of the kind that are evolved by bees? That is to say, are their _differences such as will turn the scale for or against the visits of the bees_? If one were less, another more easily seen by the bees; or if one were more fragrant, or had a fragrance more agreeable to bees than the other, the result of the experiment would probably have been very different. One more objection has been made. It is said that the bees, although exclusively restricted, both themselves and their descendants, to a diet of flowers, are not so constant _to a particular flower_ as the theory requires. They do indeed exhibit a 'considerable amount of constancy,' and often visit a large number of flowers of the same species in succession, but the theory requires that they should not only confine themselves to this one species, but to a _single variety_ of this species. These views show that their authors have not penetrated far towards an understanding of the nature of selection. Nature does not operate with individual flowers, but with millions and myriads of them, and not with the flowers of a single spring, but with those of hundreds and thousands of years. How often a particular bee may carry pollen uselessly to a strange flower without thereby lowering the aggregate of seeds so far that the existence of the species seems imperilled, or how often she may fertilize the pistil of a useful variation with the pollen of the parent species, without interrupting or hindering the process of the evolution of the variety, no mortal can calculate, and what the theory requires can only be formulated in this way: The constancy of the bees in their visits to the flowers must be so great that, on an average, the quantity of seeds will be formed which suffices for the preservation of the species. And in regard to the transformation of a species, the attraction which the useful variety has for the bees must, on an average, be _somewhat stronger_ than that of the parent species. As soon as this is the case the seeds of the variety will be formed in preponderant numbers, although they may not all be quite pure from the first, and by degrees, in the course of generations, the plants of the new variety will preponderate more and more over those of the parent form, and finally will alone remain. In the first case we have before our eyes the proof that, in spite of the imperfect constancy of the bees, a sufficient number of seeds is produced to secure the existence of the species. Or does Mr. Bulman