hardly allow that we could have reached the summit had we been deprived of all means of cooking and heating. [Sidenote: Germless Air] On this ridge the dough refused to sour, and since our baking-powder was consumed in the fire we were henceforth without bread. A cold night killed the germ in the sour dough, and we were never again able to set up a fermentation in it. Doubtless the air at this altitude is free from the necessary spores or germs of ferment. Pasteur's and Tyndall's experiments on the Alps, which resulted in the overthrow of the theory of spontaneous generation, and the rehabilitation of the old dogma that life comes only from life, were recalled with interest, but without much satisfaction. We tried all sorts of ways of cooking the flour, but none with any success. Next to the loss of sugar we felt the loss of bread, and in the food longings that overtook us bread played a large part. On Friday, 30th May, the way had been prospected right up to the pass which gives entrance to the Grand Basin; a camping-place had been dug out there and a first load of stuff carried through and cached. So on that morning we broke camp, and the four of us, roped together, began the most important advance we had made yet. With stiff packs on our backs we toiled up the steps that had been cut with so much pains and stopped at the cache just below the cleavage to add yet further burdens. All day nothing was visible beyond our immediate environment. Again and again one would have liked to photograph the sensational-looking traverse of some particularly difficult ice obstacle, but the mist enveloped everything. Just before we reached the smooth snow slope above the range of the earthquake disturbance lay one of the really dangerous passages of the climb. [Sidenote: A Perilous Passage]