But the second time, when I lived at Gaboon, I stayed five and a half years,—far too long. During the first three years at Gaboon T had fever once every two or three months. I became very familiar with its preceding symptoms—physical exhaustion for several days, such that the least effort induced painful weariness and a frequent heavy sigh; aching of head and limbs; chills alternating rapidly with feverish heat, and a terrible temper. At the end of the third year I had a very severe fever which, instead of yielding to quinine the third day, became much worse, and the natives carried me in a hammock to the French hospital. There I remained for five weeks. But after that I had no more fever, not even once, though I remained in Africa more than two years longer, which would have been absolutely impossible if the fevers had continued. The difference was in my use of quinine. At first I took quinine only with the attacks of fever, and then I took an enormous quantity. But in the later period I kept myself immune by taking it daily whether I was ill or not. I took five grains every night for those several years. People are usually greatly surprised at this and ask if such an amount of quinine was not a terrible strain upon the constitution. It was, without doubt; but not so great a strain as malarious blood, and frequent fevers, and the shock of very large doses of quinine at such times. If I had not been in greatly reduced health before I began to take it regularly it is not likely that I should have required nearly so much. But this is anticipating; for we are still on the outward voyage.