are very active, and dance about—as a rule singly, sometimes in pairs, rarely in short chains.Bruce's assistant, Surgeon Captain Matthew Louis Hughes named the disease "undulant fever" and the bacterium, Micrococcus melitensis. The source of the infection was not clear, Hughes believing it to come from soil and the bacterium inhaled from the air. Bruce reported the discovery in The Practitioner in 1887 with the conclusion:I think it will appear to be sufficiently proved: (a) that there exists in the spleen of cases of Malta fever a definite micro-organism; and (b) that this micro-organism can be cultivated outside the human body. On the latter point I may remark that I have already cultivated four successive generations. It now remains to be seen what effect, if any, this micro-organism has on healthy animals; what are the conditions of temperature, &c., under which it flourishes; where it is to be found; how it gains entrance to its human host; and many other points. All of these will take a long time to investigate. I have therefore published this preliminary note in order to draw the attention of other workers to what seems to me to be an attractive field.He was correct in his prediction that it was only in 1905 goat milk was established as the source of the infection. The discovery that the disease was transmitted from goat milk was generally attributed to Bruce himself. But an analysis of historical record in 2005 revealed that Themistocles Zammit, one of the members of the commission, was the one who experimentally demonstrated the origin of the bacterium from goat milk. The genus Micrococcus was changed to Brucella in honour of Bruce and is accepted as a valid name. Accordingly, the disease has been renamed brucellosis. The fly disease and sleeping sickness When Bruce was transferred to South Africa, he was sent to Zululand to investigate the outbreak of animal disease which the natives called nagana, and the Europeans, the fly disease. In 1894, he and his wife found that the disease was prevalent among cattle, donkey, horses and dogs. They collected blood samples from such infected animals, and found parasites which Bruce identified correctly as a type of "Haematozoon" (attributed to protozoans that are blood parasites), as he described in his report in 1895:At this point I think it will be convenient to give a definite description of the parasite discovered by me