内容简介：
I do not quite know how it happened, my recollection of the whole matter ebbing in a somewhat clouded condition. I fancy I had gone somewhere on a botanizing expedition, but whether at home or abroad I don't know. At all events, I remember that I had taken up the study of plants with a good deal of enthusiasm, and that while hunting for some variety in the mountains I sat down to rest on the edge of a ravine. Perhaps it was on the ledge of an overhanging rock; anyhow, if I remember rightly, the ground gave way all about me, precipitating me below. The fall was a very considerable one-probably thirty or forty feet, or more, and I was rendered unconscious. How long I lay there under the heap of earth and stones carried down in my fall it is impossible to say: perhaps a long time; but at last I came to myself and struggled up from the debris, like a mole coming to the surface of the earth to feel the genial sunshine on his dim eyeballs. I found myself standing (oddly enough, on all fours) in an immense pit created by the overthrow of a gigantic dead tree with a girth of about thirty or forty feet. The tree itself had rolled down to the bottom of the ravine; but the pit in which it had left the huge stumps of severed roots was, I found, situated in a gentle slope at the top of the bank