CHAPTER XVIII 



MALTA OR MEDITERRANEAN FEVER 



Micrococcus Melitensis (Bruce); Bacillus Melitensis 



(Babes) 



General Characteristics. — A non-motile, non-flagellate, non-sporogenous 

 non-chromogenic, non-liquefying, pathogenic coccus, staining by the ordinary 

 methods, but not by Gram's method; characterized by remarkably slow growth 

 and by pathogenic action upon monkeys. 



In 1877, while working in Malta, Bruce* succeeded in finding in 

 every fatal case of Malta fever a micrococcus which could be isolated 

 in pure cultures from the spleen, liver, and kidney, which grew readily 

 on artificial media, and which, when injected into monkeys, produced 

 the disease. 



Morphology. — -Micrococcus melitensis, as Bruce called it, is a 

 round or slightly oval organism measuring about 0.3 fjt in diameter. 

 It is usually single, sometimes in pairs, but never in chains. When 

 viewed in the hanging drop it is said to exhibit active "molecular" 

 movements, but is not motile and has no flagella. Babesf declares 

 it to be a bacillus. 



Staining. — It stains well with aqueous solutions of the anilin dyes, 

 but not by Gram's method. 



Thermal Death Point. — -This has been fixed by Dalton and EyreJ 

 at S7-S°C. 



Cultivation. — The best medium for its cultivation is said to be 

 ordinary agar-agar. After inoculating, by a puncture, from the 

 spleen of a fatal case of Malta fever, the tubes should be kept at 37°C. 

 The growth first appears after several days, in the form of minute 

 pearly white spots scattered around the point of puncture and along 

 the needle path. After some weeks the colonies grow larger and join 

 to form a rosette-like aggregation, while the needle tract becomes 

 a solid rod of yellowish-brown color. After a lapse of months the 

 growth still remains restricted to the same area and its color deepens 

 to buff. 



When the sloping surface of inoculated agar-agar is examined by 

 transmitted hght, the appearance of the colonies is somewhat dif- 

 ferent. At the end of nine or ten days, if kept at 37°C., some of the 

 colonies have a diameter of 2 to 3 mm. They are round in form, have 

 an even contour, are slightly raised above the surface of the agar- 



* "Practitioner," xxxiv, p. 161. 



t KoUe and Wassermann, "Die Pathogene Mikroorganismen," in, p. 443. 

 X "Jour, of Hygiene," 1904, iv, p. 157. 



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