§ 1. Specific form and chemical constitution—The wide distribution of crystalline forms—Organization of crystals—Law of relation between specific form and chemical constitution—Value of form as a characteristic of brute and living beings—Parentage, living beings and mineral parentage—Iso-morphism and the faculty of cross-breeding—Other analogies. § 2. Acquisition and re-establishment of the specific form—Mutilation and regeneration of crystals—Mechanism of reparation. § 1. _Specific Form and Chemical Constitution._—In the enumeration which we have made of the essential features of vitality there are three that are, so to speak, of the highest value. They are, in the order of their importance:—The possession of a specific form; the faculty of growth or nutrition; and finally, the faculty of reproduction by generation. By restricting our comparison between brute bodies and living bodies to these truly fundamental characters we sensibly restrict the field, but we shall see that it does not disappear. _Wide Distribution of Crystalline Forms._—The consideration of specific forms shows us that in the mineral world we need only consider crystallized bodies, as they are almost the only ones that possess definite form. In restricting ourselves to this category we do not limit our field as much as might be supposed. Crystalline forms are very widely distributed. They are, in a measure, universal. Matter has a decided tendency to assume these forms whenever the physical forces which it obeys act with order and regularity, and when their action is undisturbed by accidental occurrences. In the same way, too, living forms are only possible in regulated environments, under normal conditions, protected from cataclysms and convulsions of nature. The possession of a specific form is the most significant feature of an organized being. Its tendency, from the time it begins to develop from the germ, is toward the acquirement of that form. The progressive manner in which it seeks to realize its architectural plan in spite of the obstacles and difficulties that arise—healing its wounds, repairing its mutilations—all this, in the eyes of the philosophical biologist, forms what is perhaps the most striking characteristic of a living being, that which best shows its unity and its individuality. This property of organogenesis seems pre-eminently the vital property. It is not so, however, for crystalline bodies possess it in an almost equal degree. The parallel between the crystal and a living being has been often drawn. I will not reproduce it here in detail. My sole desire, after sketching its principal features, is to call attention to the new information that has been brought out by recent investigations.