468 



Malta or Mediterranean Fever 



agar, and are smooth and shining in appearance. On examining the 

 colonies by transmitted light, the center of each is seen to be yellow- 

 ish, while the periphery is bluish-white in color. The same colonies 

 by reflected light appear milky-white. Colonies on the surface 

 of the agar-agar are found to be no larger than hemp-seed after 

 a couple of months of cultivation. 



When kept at 25C., no colonies become visible to the naked eye 

 before the seventh day; at 37C., before the third or fourth day. 



In bouillon culture kept at 37C., diffuse clouding of the medium 

 occurs in three or four days. There is no scum on the surface. No 

 indol is formed. In sugar bouillon there is no fermentation. 



In milk the organism grows slowly without coagulation and with- 

 out acid production. 



The growth in gelatin takes place at room temperature with 



\ 



Fig. 177. Micrococcus melitensis. 



great slowness, first appearing in about a month, and no liquefac- 

 tion of the medium occurs. 



No growth takes place on boiled potato. 



Plate cultures are not adapted to the study of the organism be- 

 cause of its extreme slowness of growth. 



Bacteriologic Diagnosis. The specific agglutinative effect of the 

 serum can be made use of for the purpose of diagnosis. This has 

 been studied by Wright,* Birt and Lamb,f and later by Bassett- 

 Smith.t 



All of the observers have shown that the agglutinative reaction 

 takes place both with living and dead cultures of the Micrococcus 

 melitensis, but that to make the diagnosis dilutions of serum equal 

 to about i : 30, never greater than i : 50, must be used. Birt and 



* "Lancet," 1897, March 6; "Brit. Med. Jour.," 1897, May 15. 



t Ibid., 1899, n, p. 701. 



t "British Med. Jour.," 1902, n, p. 861. 



