SPECIFIC INFECTIOUS DISEASES PRODUCED BY COCCI 221 



succeeded in producing the disease in horses by subdural injec- 

 tions of pure cultures. Other organisms have been found in similar 

 outbreaks by other investigators. Careful study of the relation- 

 ship of these organisms to the diseases must be made before con- 

 clusions as to their importance as an etiologic factor would be 

 justified. This epizootic infection should not be confused with the 

 far more common type of so-called meningitis produced by forage 



poisoning. 



Micrococcus mclitcnsis 



Diseases Produced. Malta fever in the goat and in man; 

 Mediterranean fever. 



Bruce, in 1887, discovered a microorganism in the spleen of 

 men dead from Malta or Mediterranean fever. Since that time 

 it has been studied carefully by numerous investigators, and its 

 relationship to the disease is well established. 



Distribution. The disease is known to occur in all the countries 

 bordering on the Mediterranean, in southern Asia, South Africa, 

 the Philippines, and some of the islands of the West Indies. 



Morphology and Staining. The organism is a small ' coccus, 

 about 0.4 [A in diameter, usually in pairs, occasionally in short 

 chains. Possibly it should be classed as a Streptococcus. Rarely, 

 forms longer than broad may be observed, especially in cultures 

 kept at temperatures below the optimum. These are probably 

 involution forms. The organism stains well with ordinary anilin 

 dyes, but is gram-negative. 



Isolation and Culture. It may be isolated from the spleen 

 during life or after death in pure culture, or by plating. The 

 individual colonies on agar in three days are small and dew-drop- 

 like, and continue to increase in size for some time. There is no 

 marked peculiarity of growth upon any of the artificial media, 

 although the organism may be cultivated readily on any of them. 

 Milk is not changed. 



Physiology. The M. melitensis does not produce acid from any 

 of the carbohydrates. Desiccation does not destroy it quickly, 

 for the organism has been found to remain alive and virulent when 

 dried for a considerable time. Pasteurization is fatal. 



Pathogenesis. The disease is a true bacteremia. Inoculation 

 of pure cultures reproduces the disease in the goat, cow, and mon- 



