254 MANUAL OF BACTERIOLOGY. 



patient, with a known pure culture of Micrococcus melitensis.* 

 For this purpose a suspension of an agar culture is made in 

 normal salt solution. The diluted serum is added so as to 

 secure a dilution of about 1-50, but the dilutions used have 

 varied widely. Precipitation quickly follows agglutination. 

 According to Craig, the test may be made on a shde, examin- 

 ing with the microscope as for the typhoid bacillus (see Serum- 

 test for Typhoid Fever). 



Diplococcus intracellularis meningitidis.f — Found in 

 the exudate of cerebro-spinal meningitis by Weichselbaum; 

 a micrococcus about the size of the common pyogenic cocci; 

 grows in fours, but more often in pairs consisting of two hemi- 

 spheres separated by an interval which does not stain; usually 

 found within the pus-cells, in which respect it resembles the 

 gonococcus. It is stained by ordinary methods with the aniline 

 dyes, and is decolorized by Gram's method. It does not grow 

 at the room temperature, but only in the incubator; gelatin 

 is not available as a culture-medium. There is no growth on 

 potato and scanty growth on agar or in bouillon. The devel- 

 opment is most abundant upon LofHer's blood-serum, when 

 round, white, shining, viscid-looking colonies with sharp out- 

 lines may be seen in twenty-four hours. The serum is not 

 Hquefied. Upon agar, or better upon glycerin-agar, the colo- 

 ,nies are flat, round, translucent, viscid-looking, having a yel- 

 lowish-brown color under the low power. The organism 

 should be transplanted to fresh media frequently, as it rapidly 

 loses its power of reproduction. Many of the tubes inoculated 

 with the original material or with pure cultures show no growth. 



* Musser and Sailer. Philadelphia Medical Journal. December 31, 1898, 

 July 8, 1899. Strong and Musgrove. Ibid. November 24, 1900. Curry. 

 Journal Medical Research. Vol. VI. 1901. 



t The writer is indebted for the brief statement which it is possible to give 

 here chiefly to the exhaustive Report to the Massachusetts Board of Health 

 by Councilman, Mallory and Wright, 1898. The photograph was made from 

 a preparation kindly furnished by Dr. Mallory. 



