In all the world there is no force able to extend or prolong our sensibility beyond its fixed term; which may be a reflection upon the poverty of our means of apprehension. We would not hear the crash of two colliding planets as loudly as the piercing of our ear-drums by a pin-point, and to be burned alive in some conflagration is for the individual as though the universe went up in flame, since for those few seconds of his agony the intensity of the heat of his burning house is as great upon him as the fires of an incandescent world. A heart struck by a fragment of bursting shell would feel no more if it was caught up and crushed between clashing faces of rock. So by means of our senses we can measure against our being the greatest physical catastrophes: we can know the supreme degree of our faculty for feeling pain without calling for a clash of worlds to prove it. The limitations of our senses are such that beyond a quite-near point they can register no advance at all. It is all the same sensation whether we fall three hundred or thirty thousand feet. Its illness made the young sequoia dull to its circumstances, while the forest giant all the while responded to each vibration of its environment. On some days its sap seemed in easy relation with the air and scents and light raining upon it, as if a mysterious fluid somewhere in these many elements was making eager its stomata and dissolving the material resistance of the fibres which cut off the tree's vital fluid from the outer air. At other times, for no clear reason this sympathy between sap and outer world would grow difficult. When ill-health overtakes us, it closes off from exterior contact the private world in which we exist: but not completely: we are not driven to subsist only on our internal vitality. From there does come the impulse or continuity which leads us up to action: but this energy is reinforced by means existing independently of us, and yet influencing us to our inmost soul. Our passions come to birth within us, truly: but their growth and final efflorescence may be due to a variety of vibrations sent from without. Our loves and braveries and hates are coloured by powers beyond our will's control. A single sentiment may express itself in divers shapes according to the circumstances in which we move. A passionate outburst may be one in a closed room, another in a street, quite different in open country. The giant tree felt its feelings change according to the state of the landscape over which it towered: just as men are peculiarly liable to be strong or weak, safe or fearful, forthcoming or callous according to their attitude, their stage-setting, the occult influences which hem them in. Otherwise our likes and dislikes, our joys and sorrows would not move us to different expressions of temper in different places and conditions.