"Give me your arm as I walk homeward, and I will tell you the conclusion to which I have come." I rose, the old man leaned on me, and we went down the valley along the craggy ridges of the winding creek. The woodland on the opposite bank was vocal with the chirp and croak and chatter of Australian birds,--all mirthful, all songless, save that sweetest of warblers, which some early irreverent emigrant degraded to the name of magpie, but whose note is sweeter than the nightingale's, and trills through the lucent air with a distinct ecstatic melody of joy that dominates all the discords, so ravishing the sense, that, while it sings, the ear scarcely heeds the scream of the parrots. [1] Creek is the name given by Australian colonists to precarious water Courses and tributary streams. CHAPTER LXXI. "You may remember," said Julius Faber, "Sir Humphry Davy's eloquent description of the effect produced on him by the inhalation of nitrous oxide. He states that he began to lose the perception of external things; trains of vivid visible images rapidly passed through his mind, and were connected with words in such a manner as to produce perceptions perfectly novel. 'I existed,' he said, 'in a world of newly-connected and newly-modified ideas.' When he recovered, he exclaimed: 'Nothing exists but thoughts; the universe is composed of impressions, ideas, pleasures, and pains!' "Now observe, that thus a cultivator of positive science, endowed with one of the healthiest of human brains, is, by the inhalation of a gas, abstracted from all external life,--enters into a new world, which consists of images he himself creates and animates so vividly that, on waking, he resolves the universe itself into thoughts." "Well," said I, "but what inference do you draw from that voluntary experiment, applicable to the malady of which you bid me hope the cure?" "Simply this: that the effect produced on a healthful brain by the nitrous oxide may be produced also by moral causes operating on the blood, or on the nerves. There is a degree of mental excitement in which ideas are more vivid than sensations, and then the world of external things gives way to the world within the brain.[1] But this, though a suspension of that reason which comprehends accuracy of judgment, is no more a permanent aberration of reason than were Sir Humphry Davy's visionary ecstasies under the influence of the gas. The difference between the two states of suspension is that of time, and it is but an affair of time with our beloved patient. Yet prepare yourself. I fear that the mind will not recover without some critical malady of the body!" "Critical! but not dangerous?--say not dangerous! I can endure the pause of her reason; I could not endure the void in the universe if her life were to fade from the earth." "Poor friend! would not you yourself rather lose life than reason?"