MICROCOCCUS INTRACELLULARIS MENINGITIDIS 



373 



Morphology and Staining. Stained in the spinal fluid from an in- 

 fected patient, the meningococcus bears a striking similarity to the gon- 

 ococcus. The microorganisms appear intra- and extracellularly, usually 

 in diplococcus groups, sometimes as tetrads, or even in larger agglomer- 

 ations. The individual diplo-forms are flattened on the sides facing each 

 other, presenting somewhat the biscuit-form of the gonococcus. The 

 variation in size of the cocci in the same smear is a noticeable feature 



FIG. 78. MENINGOCOCCUS IN SPINAL FLUID. 



and of some diagnostic importance. This dissimilarity in size is notice- 

 able also in cultures, which, especially when older than twenty-four 

 hours, contain forms double or even triple the size of the average coccus. 

 These may possibly be involution forms. 



The meningococcus is non-motile and non-spore forming. It 

 stains easily with all the usual aqueous aniiin dyes. Its behavior 

 toward Gram's stain was long a subject of controversy, owing to the 

 error of Jaeger, 1 who claimed to have found it Gram-positive. There 



1 Jaeger, Zeit. f. Hyg., xix, 1895. 



