452 MALTA FEVER. 



test Wright and Smith have shown that it occurs also in some 

 parts of India, and it has also been observed in the United States 

 and Porto Rico (W. I.). There can be little doubt that its dis- 

 tribution will be found to be much wider than was formerly sup- 

 posed. Although from its symptomatology and pathological 

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

 known under various names, its precise etiology was unknown 

 till the publication of the researches of Surgeon-Major Bruce 

 in 1887. From the spleen of patients dead of the disease he 

 cultivated a characteristic organism, now known as the micrococ- 

 cus melitensis > and by means of inoculation experiments estab- 

 lished its causal relationship to the disease. His results have 

 been confirmed by other observers, and additional confirmatory 

 evidence has been supplied by means of serum diagnosis, as 

 will be described below. Bacteriological methods have there- 

 fore been the means of differentiating the , disease, and also of 

 affording a more exact basis for diagnosis. 



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 perspirations, 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 swell- 

 ing ; in the kidneys there may be in addition glomerular nephri- 

 tis. 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 .5 /u, 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. 154). (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.) 



