But there was grisly hope left in the old Viking. “_At present_ it is impossible,” he said, while he believed that somewhere, somewhen, men may be found, in the mass, who will be glad to die for truth. And as you will see, in a story of a band of American buck-privates in another chapter, there are beginnings of such spirit even now. But when great armies of men so offer themselves, to fight death, just as they now delight to fight each other, it will be because they are led on by captains such as David Bruce. CHAPTER X ROSS VS. GRASSI MALARIA I The last ten years of the nineteenth century were as unfortunate for ticks, bugs, and gnats as they were glorious for the microbe hunters. Theobald Smith had started them off by scotching the ticks that carried Texas fever; a little later and six thousand miles away David Bruce, stumbling through the African bush, got onto the trail of the tsetse fly, accused him, convicted him. How melancholy and lean have been the years, since then, for that murderous tick whose proper name is _Bo-ophilus bovis_, and you may be sure that since those searchings of David Bruce, the tsetses have had to bootleg for the blood of black natives and white hunters, and missionaries. And now alas for mosquitoes! Malaria must be wiped from the earth. Malaria can be destroyed! Because, by the middle of 1899, two wrangling and not too dignified microbe hunters had proved that the mosquito--and only one particular kind of mosquito--was the criminal in the malaria mystery.