Its own new discoveries and progress have taken civilized humanity by surprise. It has had no time to adapt itself to its changed conditions of life. We know that our organs acquire by exercise an ever greater functional capacity, that they develop by their own activity, and can respond to nearly every demand made upon them; but only under one condition--that this occurs gradually, that time be allowed them. If they are obliged to fulfil, without transition, a multiple of their usual task, they soon give out entirely. No time was left to our fathers. Between one day and the next, as it were, without preparation, with murderous suddenness, they were obliged to change the comfortable creeping gait of their former existence for the stormy stride of modern life, and their heart and lungs could not bear it. The strongest could keep up, no doubt, and even now, at the most rapid pace, no longer lose their breath, but the less vigorous soon fell out right and left, and fill to-day the ditches on the road of progress. To speak without metaphor, statistics indicate in what measure the sum of work of civilized humanity has increased during the half-century. It had not quite grown to this increased effort. It grew fatigued and exhausted, and this fatigue and exhaustion showed themselves in the first generation, under the form of acquired hysteria; in the second, as hereditary hysteria. The new æsthetic schools and their success are a form of this general hysteria; but they are far from being the only one. The malady of the period shows itself in yet many other phenomena which can be measured and counted, and thus are susceptible of being scientifically established. And these positive and unambiguous symptoms of exhaustion are well adapted to enlighten the ignorant, who might believe at first sight that the specialist acts arbitrarily in tracing back fashionable tendencies in art and literature to states of fatigue in civilized humanity.