_Hypothesis of Pyrozoa._—W. Preyer declined to accept this cosmic transmigration of the simplest living beings, nor would he allow the intervention of other worlds into the history of our own. Life, according to him, must have existed from all time, even when the globe was an incandescent mass. But it was not the same life as at present. Vitality must have undergone many profound changes in the course of ages. The _pyrozoa_, the first living beings, vulcanians, were very different from the beings of the present day that are destroyed by a slight elevation of temperature. No doubt this theory of pyrozoa, proposed by W. Preyer in 1872, seems quite chimerical, and akin to Kepler’s dreamy visions. But in a certain way it accords with contemporary ideas concerning the life of _matter_. It is related to them by the evolution which it implies in the materials of the terrestrial globe. According to Preyer, primitive life existed in fire. Being igneous masses in fusion, the pyrozoa lived after their own manner; their vitality, slowly modified, assumed the form which it presents to-day. Yet, in this profound transformation their number has not varied, and the total quantity of life in the universe has remained unchanged. Here we recognize the ideas of Buffon. These cosmozoa, these pyrozoa, have a singular resemblance to the _organic molecules_ of “live matter” of the illustrious naturalist—distributed everywhere, indestructible, and forming living structures by their concentration. But we must leave these scientific or philosophical theories, and come to arguments based upon facts. It is in a spirit quite different from that of the poets, the metaphysicians, and the more or less philosophical scientists that the science of our days looks at the more or less obscure vitality of inanimate bodies. It claims that we may recognize in them, in a more or less rudimentary state, the action of the factors which intervene in the case of living beings, the manifestation of the same fundamental properties. CHAPTER III. ORGANIZATION AND CHEMICAL COMPOSITION OF LIVING AND BRUTE MATTER. Laws of the organization and of the chemical composition of living beings—Relative value of these laws; vital phenomena in crushed protoplasm—Vital phenomena in brute bodies.