“Trypanosomes--these are!” cried Bruce, and he hurried to show them to his wife. In all animals sick with nagana they found these finned beasts, in the blood they were, and in the fluid of their puffy eyelids, and in the strange yellowish jelly that replaced the fat under their skins. And never a one of them could Bruce find in healthy dogs and horses and cows. But as the sick cattle grew sicker, these vicious snakes swarmed more and more thickly in their blood, until, when the animals lay gasping, next to death, the microbes writhed in them in quivering masses, so that you would swear their blood was made up of nothing else.... It was horrible! But how did these trypanosomes get from a sick beast to a healthy one? “Here on the hill we can keep healthy animals in the same stables with the sick ones--and never a one of the sound animals comes down ... here on the hill no cow or horse has ever been known to get nagana!” muttered Bruce. “Why?...” He began to dream experiments, when the long arm of the Authorities--maybe it was that dear old Director-General remembering--found him again: Surgeon-Major Bruce was to proceed to Pietermaritzburg for duty in the typhoid epidemic raging there. III Only five weeks they had been at this work, when they started back to Pietermaritzburg, ten miles a day by ox-team through the jungle. He started treating soldiers for typhoid fever, but as usual--thief that he was--he stole time to try to find out something about typhoid fever, in a laboratory set up, since there was no regular one, of all places--in the morgue. There in the sickening vapors of the dead house Bruce puttered in snatched moments, got typhoid fever himself, nearly died, and before he got thoroughly better was sent out as medical officer to a filibustering expedition got up to “protect” a few thousand square miles more of territory for the Queen. It looked like the end for him, Hely-Hutchinson’s wires got tangled--there seemed no chance ever to work at nagana again; when the expedition had pierced a couple of hundred miles into the jungle, all of the horses and mules of this benevolent little army up and died, and what was left of the men had to try to hoof it back. A few came out, and David Bruce was among the lustiest of those gaunt hikers....