The enormous increase of hysteria in our days is partly due to the same causes as degeneracy, besides which there is one cause much more general still than the growth of large towns--a cause which perhaps of itself would not be sufficient to bring about degeneracy, but which is unquestionably quite enough to produce hysteria and neurasthenia. This cause is the fatigue of the present generation. That hysteria is in reality a consequence of fatigue Féré has conclusively demonstrated by convincing experiments. In a communication to the Biological Society of Paris, this distinguished investigator says:[58] ‘I have recently observed a certain number of facts which have made apparent the analogy existing between fatigue and the chronic condition of the hysterical. One knows that among the hysterical [involuntary!] symmetry of movements frequently shows itself in a very characteristic manner. I have proved that in normal subjects this same symmetry of movements is met with under the influence of fatigue. A phenomenon which shows itself in a very marked way in serious hysteria is that peculiar excitability which demonstrates that the energy of the voluntary movements, through peripheral stimulations or mental presentations, suffers rapid and transitory modifications co-existing with parallel modifications of sensibility, and of the functions of nutrition. This excitability can be equally manifested during fatigue.... Fatigue constitutes a true temporary experimental hysteria. It establishes a transition between the states which we call normal and the various states which we designate hysteria. One can change a normal into a hysterical individual by tiring him.... All these causes (which produce hysteria) can, as far as the pathogenic part they play is concerned, be traced to one simple physiological process--to fatigue, to depression of vitality.’ Now, to this cause--fatigue--which, according to Féré, changes healthy men into hysterical, the whole of civilized humanity has been exposed for half a century. All its conditions of life have, in this period of time, experienced a revolution unexampled in the history of the world. Humanity can point to no century in which the inventions which penetrate so deeply, so tyrannically, into the life of every individual are crowded so thick as in ours. The discovery of America, the Reformation, stirred men’s minds powerfully, no doubt, and certainly also destroyed the equilibrium of thousands of brains which lacked staying power. But they did not change the material life of man. He got up and laid down, ate and drank, dressed, amused himself, passed his days and years as he had been always wont to do. In our times, on the contrary, steam and electricity have turned the customs of life of every member of the civilized nations upside down, even of the most obtuse and narrow-minded citizen, who is completely inaccessible to the impelling thoughts of the times.