At a height of 19,000 feet we walked for some time on soft snow, which covered an ice-field with deep crevasses and cracks. We had to feel our way with great caution, particularly as by the time we reached that spot we had only the light of the moon to depend upon. As we rose higher, I began to feel a curious exhaustion that I had never experienced before. At sunset the thermometer which Kachi carried had fallen 40 deg. within a few minutes, and the sudden change in the temperature seemed to affect us all. We went on, with the exception of Bijesing, who was seized with such violent mountain sickness that he was unable to proceed. The doctor, too, a powerfully built man, was suffering considerably. His legs, he said, had become like lead, and each seemed to weigh a ton. The effort of lifting, or even moving, them required all his energy. Although he was gasping pitifully for breath, he struggled on bravely until we reached an elevation of 20,500 feet. Here he was overcome with exhaustion and pain, and he was unable to go further. Kachi Ram, the Rongba, and I went ahead, but we also were suffering, Kachi complaining of violent beating in his temples and loud buzzing in his ears. He gasped and staggered dangerously, threatening to collapse at any moment. At 21,000 feet he fell flat on the snow. He was instantly asleep, breathing heavily and snoring convulsively. His hands and feet were icy cold. What caused me more anxiety than anything was the irregular beating and throbbing of his heart. I wrapped him up in his blanket and my waterproof, and, having seen to his general comfort, I shouted to the doctor (the voice in the still air carrying for a long distance) telling him what had happened. I pushed on with the Rongba, who was now the only one of the party who had any strength left.