ETIOLOGY. — This disease prevails in summer, and in infected sections is en demic, occasionally becoming epidemic. Lack of proper sanitation favors its spread. Hughes believes that the poison is conveyed in the air and is related to defective drainage, while Bruce believes that water is the carrier. Young, healthy adults are the chief victims of this dis ease; the disease is non-contagious. An organism called the micrococcus meliten sis by Bruce, its discoverer, is present in all cases, having been found by him in large numbers in the spleen, but not as yet isolated from the blood. This organ ism is round or slightly oval in form, and measures, in dried preparations, about 0.33 micromillimetre in diameter. A magnifying power of from 1000 to 1500 diameters is required for its detection. Viewed in a drop of water, unstained, the microbes are seen as bright points in active molecular movement, the great ma jority of them single, a few in pairs, and sometimes in chains. They possess no power of spontaneous movement. They can readily be stained in a watery solution of gentian-violet, but they become decol orized by Gram's method. Alcohol at once removes all color from the micro even after fixing them with ' osmic acid, corrosive sublimate, or tannic acid. In nutrient peptonized broth, kept at 98.6° F., no change is visible for the first few days, but after some time the fluid becomes decidedly cloudy without any formation of pellicle on the surface.
The best culture-medium for this coccus is a 1.5-per-cent. peptonized agar-agar beef-jelly.
The character of the mierococcus meli tensis has been investigated by H. E. Durham, who has found that inoculations into monkeys produce a disease similar to that in man, and the micrococcus can be isolated from the infected animal. A characteristic serum-reaction is present. It is probable, from Durham's experi ments upon animals, that the specific coccus may be isolated from the urine even after apparent recovery.
Bruce isolated the specific organism of Malta- fever—micrococcus melitensis from the spleens of nine patients who had succumbed to that disease, and placed the study of the affection upon a inure definite workiw• basis. Personal case in which, as there was a question of typhoid fever, Widal's test was used, with the result that agglutination was not obtained. Treatment of the pa tient's blood-serum with a pure culture of the micrococens melitensis caused the appearance of the agglutination phe nomenon in a few minutes, thus estab lishing the diagnosis of Malta fever. Torras v Pascual (Rev. d. Cien. M6d. d. Barcelona, No. 11, 1903).