“After all, the sanitation and the agriculture of today are still in the rudimentary stage. The science of our time has attacked but a little department of the field of human disease, but even so, it spreads its operations very steadily and persistently. Our agriculture and horticulture destroy a weed just here and there and cultivate perhaps a score or so of wholesome plants, leaving the greater number to fight out a balance as they can. We improve our favourite plants and animals--and how few they are--gradually by selective breeding; now a new and better peach, now a seedless grape, now a sweeter and larger flower, now a more convenient breed of cattle. We improve them gradually, because our ideals are vague and tentative, and our knowledge is very limited; because Nature, too, is shy and slow in our clumsy hands. Some day all this will be better organized, and still better. That is the drift of the current in spite of the eddies.”