MICROCOCCUS MELITENSIS 501 



been worked out, it has been found to occur also in India, 

 China, South Africa, and in some parts of North and South 

 America, its distribution being much wider than was formerly 

 supposed. Although from its symptomatology and pathological 

 anatomy it had been recognised as a distinct affection, and was 

 knowu under various names, its precise etiology was unknown till 

 the publication of the researches of Surg. -General Bruce in 1887. 

 From the spleen of patients dead of the disease he cultivated a 

 characteristic organism, now known as the Micrococcus melitensis, 

 and by means of inoculation experiments established its causal 

 relationship to the disease. Wright and Semple applied the 

 agglutination test to the diagnosis of the disease, and in 1904 

 the mode 1 of spread of the disease was fully studied by a Com- 

 mission, whose work demonstrated that goat's milk is the chief 

 means of infection. 



The duration of the disease is usually long — often two or 

 three months, though shorter and much longer periods are met 

 with. Its course is very variable, the fever being of the con- 

 tinued type with irregular remissions. In addition to the usual 

 symptoms of pyrexia, there occur profuse perspiration, pains 

 and sometimes swellings in the joints, occasionally orchitis, 

 whilst constipation is usually a marked feature. The mortality 

 is low — about 2 per cent. (Bruce). 



In fatal cases the most striking post-mortem change is in the 

 spleen. This organ is enlarged, often weighing slightly over a 

 pound, and in a condition of acute congestion ; the pulp is soft 

 and may be diffluent, and the Malpighian bodies are swollen and 

 indistinct. In the other organs the chief change is cloudy 

 swelling ; in the kidneys there may be in addition glomerular 

 nephritis. The lymphoid tissue of the intestines shows none of 

 the changes characteristic of typhoid fever. 



Micrococcus melitensis. — This is a small, rounded, or slightly 

 oval organism about '4 ft in diameter, which is specially abundant 

 in the spleen. It usually occurs singly or in pairs, but in 

 cultures short chains are also met with (Fig. 151). (Durham 

 has shown that in old cultures kept at the room temperature 

 bacillary forms appear, and we have noticed indications of such 

 in comparatively young cultures ; the usual form is, however, 

 that of a coccus.) It stains fairly readily with the ordinary 

 basic aniline stains, but loses the stain in Gram's method. It 

 is generally said to be a non-motile organism. Gordon, how- 

 ever, is of a contrary opinion, and has demonstrated that it 

 possesses from one to four flagella, which, however, are difficult 

 to stain. In the spleen of a patient dead of the disease it 



