"This fact is indisputable, taken from a purely scientific and practical view. We cannot experiment upon man, but it is possible to do so upon animals. Human physiology employs the means to enlighten us upon our organic functions. Physicians have carried to the sick-bed the result of their investigations upon animal life. Anthropology also, we shall see, has derived useful lessons from beings who are essentially our inferiors. Anthropology should descend still lower than animals to enlighten us thoroughly. Vegetables are not animals any more than animals are men; but man, animals, and vegetables are linked together in the same living organization. By this only, they are distinguished from the minerals, which are neither the one nor the other, and by certain general facts known to all. "All organized beings have a limited duration, all are created small and weak, all grow and become strong; during a part of their existence, all decrease in energy and vitality, sometimes also in size, then die. During life, all organized beings have need of nourishment. Before dying, all produce, either by a seed or by an egg, (I speak of species, not individuals,) which is true of the species that seem to come directly from a shoot, a layer, or a graft; all proceed from a grain, or an egg. Thus, all these great phenomena, common to all living organized beings, including man as well as plants, suppose a general law for their government. Science confirms this conclusion every day, which is not an invention of reasoning alone, but is regarded as an _experienced fact_. Further explanations are not necessary to show the magnificent result. "How admirable, that man and the smallest insect, that the lord of the soil and the smallest plant, are attached one to the other, by the same links, and that the entire living creation forms together a perfect harmony! "In this communion, and in certain phenomena of this accordance with certain laws, equally common, there results one consequence upon which I would not too strongly insist. Whatever may be the questions relating to man, that we have to examine whenever these touch upon any one of the phenomena that are common to all living organized beings, we must not only investigate animal life, but also vegetable life, if we would wish to find the truth. {69} "When one of these questions is proposed, what can we truthfully urge in reply? We must examine man under the general laws that govern other living organized beings. If the investigation tends to make man an exception to these general laws, we shall know it is false. If you resolve the problem so as to include man in the general laws, you may be sure that you are scientific and correct. With these proofs, and these only, I proceed to the second question of anthropologists. Are there several species of men, or does there exist but one, comprising several races?