We now see that in our body some mechanism is lacking which would act as a curb to save us when we fall. It is one of the greatest imperfections of our nature that at every false step we may be thrown down and crushed, as though in the wheels of a machine. We may compare ourselves to those poor wretches who intoxicate themselves with opium or alcohol, and who, at last, cannot stop themselves on their downward path of intemperance, because if they cease drinking, opium-smoking, or opium-eating, there is an immediate aggravation of the morbid phenomena and tremor with which they are afflicted. The primary cause of their disease now assuages the disease itself; it is a remedy which soothes them and slowly kills them. Physiology is still too imperfect to make intelligible to us the intricate network of causes which impel man to act in one way rather than in another. Our eye cannot discern many important factors in human actions which, perhaps, will become evident to future generations. Chronicles, annals, biographies offer insufficient data and details too imperfectly known. I do not know when it will be possible to others to penetrate, as Taine did, far into the history of nations, to discover the biological laws governing the rise and fall of the greatness of a people. I only know that I am saddened and perplexed at the unhappy thought that, as the brain of the human race grows more perfect, the more sensitive and excitable will it become, the more will emotional desires wax within it. V Courage springs from three sources: nature, education, and conviction. Each of these may so preponderate as to compensate for the deficiency of the others. It is useless to say to a man, 'You must be courageous,’ in order to make him so. Every day we see that the example of parents, education, admonitions, do not suffice to implant virtue in the children. There is a vital element in education which must be prepared long before, like the soil and the seed before the harvest; parents must bequeath to their children the inheritance of a constitution, robust and full of courage. Fear attacks and nullifies every effort of the will in such a manner that it has always been esteemed a deed of heroism to combat and subdue it utterly. Alexander of Macedonia offered up sacrifices to Fear before he went to battle, and Tullus Hostilius erected temples and consecrated priests to it. In the museum of Turin there are two Roman medals, one of which bears the impression of a terrified woman, the other the head of a man with hair on end and frightened, staring eyes. They were struck by the consuls of the family of the Hostilii in remembrance of the vows made to propitiate Fear, which threatened to invade the ranks of the soldiers, who thereupon were led to victory.