How he enjoyed hearing of other men trying to kill themselves to find out! His last African foray was in 1911--he stayed until 1914. He was near sixty; his blacksmith’s strength was beginning to crack from a nasty infection of his air-tubes got from I know not what drenching rains or chills of high tropic nights. But a new form of sleeping sickness--terrible stuff that killed in a few months instead of years--had just broken out in Nyassaland and Rhodesia. There was a great scientific quarrel on. Was the trypanosome causing this disease some new beast just out of the womb of Nature--or was it nothing else than Bruce’s old parasite of nagana, tired of butchering only cows, dogs and horses, and now learning to kill men? Bruce went to work at it. A German in Portuguese East Africa said: “This trypanosome is a new kind of bug!” Bruce retorted: “On the contrary, it is nothing but the nagana germ hopping from cows to men.” Then this German, his name was Taute, took the blood of an animal about to die from nagana, and shot five cubic centimeters of it--it held millions of trypanosomes--under his own skin: to prove the nagana parasite does not kill men. And he let scores of tsetse flies bite him, flies whose bellies and spit-glands were crammed with the writhing microbes--he did these things to prove his point! Was Bruce shocked at this? Listen to him, then: “It is a matter for some scientific regret that these experiments were not successful--though we can ill spare our bold and somewhat rash colleague--for then the question would have been answered.... As it is, these negative experiments prove nothing. It may be that only one man in a thousand would become infected that way.” Merciless Bruce! Poor Taute! He tried conscientiously to kill himself--and Bruce says it is too bad he did not die. He made the ultimate gesture--surely the God of searchers will reward him; then Bruce (and he is right) criticizes the worth of Taute’s lone desperate experiment! Nyassaland was the last battlefield of Bruce against the sleeping sickness, and it was his most hopeless one. For here he found that the _Glossina morsitans_ (that is the name of the tsetse carrier of the sickness) does not make its home only on the shores of lakes and rivers, but buzzes and bites from one end of Nyassaland to the other; there is no way of running away from it, no chance of moving nations out from under it here.... Bruce stuck at it, he spent years at measurements of the lengths of trypanosomes--monotonous enough this work was to have driven a subway ticket chopper mad--he was trying to find out whether the nagana and this new disease were one and the same thing. He ended by not finding out, and he finished with this regret: that it was _at present_ impossible to do the experiment to clinch the matter one way or the other. That experiment was the injection of the nagana trypanosomes, not into one, or a hundred--but a thousand human beings. IX