5QO MICROBIOLOGY OF THE DISEASES OF MAN AND ANIMALS. 



riers." New cows should be suspected until found free by careful ex- 

 amination. 



Affected cows should be isolated if possible, and always milked last. 

 Their milk should be boiled and fed to hogs, and the milkers' hand suit- 

 ably disinfected. 



MALTA FEVER.* 

 Micrococcus melitensis. 



This disease is endemic along the shores of the Mediterranean, in 

 South Africa, India, China, the Philippines, and the West Indies. 



The period of incubation is usually about six to ten days. 



The ordinary variety shows an intermittent or undulatory fever 

 which may be protracted to six months or more, accompanied by consti- 

 pation and general debility with various complications such as neuralgias, 

 arthritis, orchitis, etc. Relapses occur after periods of absence of symp- 

 toms. Malignant cases are described which may be fatal in a week or 

 ten days. The mortality is 2 per cent and no characteristic pathological 

 changes are found. 



The etiological factor is M. melitensis and was described by Bruce in 

 1887. 



The organism can be obtained from the blood and in many cases from 

 the urine. The most recently reported favorable medium for blood cul- 

 tures is peptone broth with the addition of bile. 



It is generally recognized as an oval coccus, although it is also described as a bacillus. 

 Its maximum measurements have been found to be o.8/j. by 0.53/1, i ts minimum di- 

 ameters 0.55/1 by o-4/x. It occurs singly, in pairs, in irregular groups and in short chains. 

 (Recently the organism has been described as motile and possessing a single flagellum at 

 the extremity of the long diameter of the oval coccus.) It stains by ordinary aniline 

 dyes and is Gram-negative. It grows slowly at room temperature, better at body 

 temperature and does not seem to be markedly sensitive to acidity or alkalinity of reac- 

 tion. It grows aerobically. On plain agar after about forty-eight hours small 

 whitish to yellowish colonies appear. Growth has been observed in broth in eighteen 

 to twenty-four hours, on gelatin in eight or nine days, and the latter is not liquefied. 

 It has been found to grow on acid potato and in acid or alkaline urine. 



Human beings and animals eliminate the organisms in the urine, and 

 the milk of goats has been found to be a prolific source of infection. 

 With proper regulations in regard to goats' milk the disease has been 

 greatly reduced. 



* Prepared by Edward Fidlar. 



