ONE:The first part of their way was through a forest, but, as they ascended, the trees became smaller and fewer, and their character changed. At the base there were pines and oaks, but they gradually made way for beeches and birches, the latter being the last because the hardiest. From the forest they emerged upon the region of barren rock and earth and the fragments left by the eruptions of the volcano. The last eruption took place in 1707, and there have been few signs of any intention of returning activity since that date. But all around there are abundant traces of what the mountain was when it poured out its floods of lava and covered large areas with desolation. In some places the heaps of scori? appear as though the eruption, whence they came, had been but a week ago, as they are above the line of vegetation, and their character is such that[Pg 210] they undergo hardly any change from the elements from one century to another."Dear me," muttered the Doctor, "you find us rather short at present. I must think of something." He went on talking, as though to gain time. "It's quite obvious, of course, that you need more than an average person. I ought to have realised. There would be exaggerated metabolism��naturally, to sustain exaggerated function. But, of course, the��er��motive force behind this extraordinary efficiency of yours is still a mystery to me. Am I right in assuming that there is a sort of mechanism?"

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