The really appalling mortality of Europeans is a fact with which all who have any idea of casting in their lot with Africa should seriously reckon. None but those who have been on the spot, or have followed closely the inner history of African exploration and missionary work can appreciate the gravity of the situation. The malaria spares no man; the strong fall as the weak; no number of precautions can provide against it; no kind of care can do more than make the attacks less frequent; no prediction can be made beforehand as to which regions are haunted by it and which are safe. It is not the least ghastly feature of this invisible plague that the only known scientific test for it at present is a human life. That test has been applied in the Congo region already with a recklessness which the sober judgment can only characterize as criminal. It is a small matter that men should throw away their lives, in hundreds, if need be, for a holy cause; but it is not a small matter that man after man, in long and in fatal succession, should seek to overleap what is plainly a barrier of Nature. And science has a duty in pointing out that no devotion or enthusiasm can give any man a charmed life, and that those who work for the highest ends will best attain them in humble obedience to the common laws. Transcendentally, this may be denied; the warning finger may be despised as the hand of the coward and the profane. But the fact remains--the fact of an awful chain of English graves stretching across Africa. This is not spoken, nevertheless, to discourage missionary enterprise. It is only said to regulate it. To the head of Lake Nyassa in a little steam yacht is quite a sea-voyage. What with heavy seas, and head-winds, and stopping to wood, and lying-to at nights, it takes longer time than going from England to America. The lake is begirt with mountains, and storms are so incessant and so furious that Livingstone actually christened Nyassa the "Lake of Storms." The motion on anchoring at night was generally so unpleasant that one preferred then to be set on shore. My men--for I had already begun to pick up my caravan whenever I could find a native willing to go--would kindle fires all round to keep off beasts of prey, and we slept in peace upon the soft lake sand.