There are certain plants--the Dodder, for instance--which begin life with the best intentions, strike true roots into the soil, and really appear as if they meant to be independent for life. But after supporting themselves for a brief period they fix curious sucking discs into the stem and branches of adjacent plants. And after a little experimenting, the epiphyte finally ceases to do anything for its own support, thenceforth drawing all its supplies ready-made from the sap of its host. In this parasitic state it has no need for organs of nutrition of its own, and Nature therefore takes them away. Henceforth, to the botanist, the adult Dodder presents the degraded spectacle of a plant without a root, without a twig, without a leaf, and having a stem so useless as to be inadequate to bear its own weight. In the Mistletoe the parasitic habit has reached a stage in some respects lower still. It has persisted in the downward course for so many generations that the young forms even have acquired the habit and usually begin life at once as parasites. The Mistletoe berries, which contain the seed of the future plant, are developed especially to minister to this degeneracy, for they glue themselves to the branches of some neighboring oak or apple, and there the young Mistletoe starts as a dependent from the first. Among animals these _lazzaroni_ are more largely represented still. Almost every animal is a living poor-house, and harbors one or more species of _epizoa_ or _entozoa_, supplying them gratis, not only with a permanent home, but with all the necessaries and luxuries of life. Why does the naturalist think hardly of the parasites? Why does he speak of them as degraded, and despise them as the most ignoble creatures in Nature? What more can an animal do than eat, drink, and die to-morrow? If under the fostering care and protection of a higher organism it can eat better, drink more easily, live more merrily, and die, perhaps, not till the day after, why should it not do so? Is parasitism, after all, not a somewhat clever _ruse_? Is it not an ingenious way of securing the benefits of life while evading its responsibilities? And although this mode of livelihood is selfish, and possibly undignified, can it be said that it is immoral? The naturalist's reply to this is brief. Parasitism, he will say, is one of the gravest crimes in Nature. It is a breach of the law of Evolution. Thou shalt evolve, thou shalt develop all thy faculties to the full, thou shalt attain to the highest conceivable perfection of thy race--and so perfect thy race--this is the first and greatest commandment of nature. But the parasite has no thought for its race, or for perfection in any shape or form. It wants two things--food and shelter. How it gets them is of no moment. Each member lives exclusively on its own account, an isolated, indolent, selfish, and backsliding life.