Such would be the most expedient test for apparent or real death. The question occurs in the case of grains of corn in Egyptian tombs, and also of hibernating animals and reviviscent beings, and, in general, in the case of what has been called the state of _latent life_. But from the practical point of view it is extremely difficult to apply this test and to decide if the phenomena which are arrested in the grain at maturity, in Leeuwenhoek’s tardigrada,[18] and in the dried-up Anguillulidæ[19] of Baker and Spallanzani, in the encysted colpoda[20] that a drop of warm water will revive, in the animals exposed by E. Yung and Pictet to a cold of more than a 100° C. below zero, are due to the general arrest of the two forms of assimilation, or to the arrest of the manufacture and utilization of reserve-stuff alone, or finally, to the arrest of protoplasmic assimilation alone. The latter, which is already very restricted in beings in a normal condition whose growth is terminated, may fall to the lowest degree in the being which, having no functional activity, is assimilating nothing. So that, to cut the question short, the experimenter who measures the value of the exchanges between the being and the medium has seldom to do more than decide between little and nothing. Hence his perplexity. But if experiment hesitates, theory affirms: it admits _a priori_ that the movement of protoplasmic assimilation, an essential sign of vitality, is neither checked nor renewed, but proceeds continuously. [18] Bear-animalcules, Sloth-animalcules. An order of Arachnida.—TR. [19] Minute thread worms, known as paste-eels and vinegar-eels.—TR. [20] Genus of Infusoria. Colpodea cucullus is found in infusions of hay.—TR. _Is Nutrition, the Assimilating Synthesis, interrupted?_—Nevertheless, there are many reasons for suspending all judgment as to this interpretation. It is questioned by most biologists. According to A. Gautier, the preserved grain of corn and the dried up rotifera are not really alive; they are like clocks in working order, ready to tell the time, but awaiting in absolute repose the first vibration which will set them going. As for the grain, it is the air, heat, and moisture which supply the first impulse. In other words, the organization proper to the manifestation of life remains, but there is no life. The so-called arrested life is not a life.