It must be said, however, that the majority of physiologists refuse to accept this interpretation. They believe in an attenuation of the nutritive synthesis and not in its complete destruction. They think that this total suppression would be contrary to current ideas relative to the perpetuity of the protoplasm and the limited duration of the living element. The natural medium is variable, and even the mineral cannot remain eternally fixed. Still less is perennity a property of the living being. If ordinary life is for each individual of limited duration, the arrested life must also be of limited duration. We cannot believe that after an indefinitely prolonged sleep the grain of corn, or the paste-eel, or the colpoda, emerging from their torpor can resume their existence, like the Sleeping Beauty, at the point at which it was interrupted, and thus pass with a bound, as it were, through the centuries. In fact the maintenance of the vitality of grains of corn from the Egyptian tombs and their aptitude to germinate after thousands of years are only fables or the result of imposture. Maspero, in a letter addressed to M. E. Griffon on the 15th July 1901, has clearly summed up the situation by saying that the grains of corn bought from the fellahs almost always germinate, but that this is never the case with those that the experimenter himself takes from the tombs. To sum up, we must use the same language of nutrition and of life, of their uninterrupted progress, of their continuity, of their permanence, of their activity, and of their slackening. Living matter is always growing, much or little, slowly or quickly, in its reserve-stuff or in its protoplasm, for expenditure or accumulation. This inevitability of growth defines it, characterizes it, and sums up its activity. Development and the evolution of growth are consequences or aspects of nutrition. BOOK IV. THE LIFE OF MATTER. Summary: Chap. I. Universal life—Opinions of philosophers and poets—Continuity between brute and living bodies—Origin of this principle.—Chap. II. Origin of brute matter in living matter.—Chap. III. Organization and chemical composition of brute and living bodies.—Chap. IV. Evolution and transformation of brute and living bodies.—Chap. V. Possession of a specific form—Living bodies and crystals—Cicatrization.—Chap. VI. Nutrition in the living body and in the crystal.—Chap. VII. Generation in brute and in living bodies—Spontaneous generation.