MICROCOCCUS MELITENSIS 447 



means of inoculation experiments established its causal relation- 

 ship to the disease. Wright and Semple applied the agglutina- 

 tion test to the diagnosis of the disease, while within recent 

 years the mode of spread of the disease has been fully studied 

 by a Commission, and it has been 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 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 

 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 /A 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. 153). (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, however, 

 is of a contrary opinion, and has recently 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 occurs 

 irregularly scattered through the congested pulp ; it may also be 

 found in small numbers post mortem in the capillaries of various 

 organs. It may be cultivated from the blood during life in a 

 considerable proportion of cases; for this purpose 5-10 c.c. of 

 blood should be withdrawn from a vein and distributed in small 

 flasks of bouillon. The micrococcus was found by the members 

 of the Commission in the urine of Malta fever patients in 10 per 

 cent of the cases examined ; it was sometimes scanty, but some- 

 times present in large numbers. 



