"Some explanations are necessary. Examine the designs before you, and you will discover the principal varieties exhibited in the human type. You have there individuals from all parts of the world; you see that they differ considerably in color, some in their hair, others in their size, or in their peculiar features. It behooves us to ascertain if the differences that present themselves in these human groups are those of _species_, or if they merely indicate the existence of _races_ belonging to the same species. "In order to reply to this question, you must ascertain the true significance of the words _species_ and _race_. The result of the discussion depends upon these two words. Unhappily, they are often confounded and badly defined, and we become enveloped in mystery when we wish to consider them more closely. Let us then form a precise idea before entering into otherwise profitless details. "None of you certainly confound the horse with the ass; though the horse may be no larger than the dogs of Newfoundland, or though the ass should attain the size of an ordinary horse--for example, the large asses of Poitou. You will immediately say they are different species. You will say the same if you place a dog and a wolf side by side. "We call by the one name of dogs the different types, such as the spaniel, the greyhound, the lap-dog, the Newfoundland, the King Charles; and we are right. However, if we were to judge by the eyes only, and even after more minute observations, there is between the dogs I have named greater differences of color, proportion, and size, than between the horse and the ass. The latter have certainly more similarity between them than the types of dogs I have named. "If I should place a black and a white water-spaniel side by side, you would call them both spaniels, though of a different color. When we examine vegetables, it is the same thing; a red and a white rose are equally roses; pears that are sold two for a penny, are the same species as those sold at twenty cents each. "Without any doubt you have arrived at the exact conclusion of the naturalists; like them, you have resolved the questions of _species_ and _race_, which at first sight seemed, for the reasons I have given, more or less confused. "These examples fully prove that popular observation and common sense are in many things fully as reliable as the investigations of science. Were such deductions generalized into scientific language, I feel sure there would be found few if any mistakes.