PATHOGENIC BACTERIA. 253 



bourn and others, but the interpretation of their results at 

 the present time is not clear. The agglutination reaction 

 has been claimed to occur with the pneumococcus, but it does 

 not yet appear to have any practical value in diagnosis. 



Organisms related to the pneumococcus have been described 

 under the names of pseudopneumococcus* and Streptococcus 

 mucosus.f 



The organism named by Rosenbach Micrococcus pyogenes 

 tenuis is probably only a variety of the pneumococcus. 



Micrococcus melitensis. — A micrococcus found by Bruce 

 in cases of Malta fever. It is a round or slightly oval organism, 

 about 0.5 /J- in diameter, occurring singly, in pairs or in short 

 chains. It is usually said to be non-motile, though flagella 

 have been described. It is stained by ordinary aniline dyes, 

 but not by Gram's method. It grows slowly, even in the incu- 

 bator, and more slowly at ordinary temperatures. In gelatin 

 the growth is feeble ; there is no liquefaction. On agar pearly 

 white growths appear after three or four days. Bouillon 

 becomes turbid, and later a sediment is formed. On potato 

 there may be slight invisible growth. 



Malta fever occurs chiefly about the Mediterranean. It 

 has been observed in India, in the Philippine Islands and in 

 Porto Rico. 



It is a chronic febrile disease, but not very fatal, accompanied 

 by pains in the joints and perspiration. At autopsies the 

 organisms may best be recovered from the enlarged spleen. 

 Accidental infection in man has occurred from pure cultures 

 on a number of occasions. The disease may be reproduced 

 in monkeys by inoculation with pure cultures. The agglu- 

 tination reaction is positive in this disease. The diagnosis 

 is best made by applying this test to the blood-serum, of the 



♦ Richardson. Journal Boston Society o^ Medical Sciences. Vol. V. 1901. 

 f Howard. Journal Medical Research. Vol. VI. 1901. 



