MICROCOCCUS MENINGITIDIS 93 



In the diagnosis of this disease from a bacteriological 

 standpoint, the most important procedure is the 

 lumbar puncture. This is the introduction of a needle 

 into the meningeal space by entering between the 

 vertebrae of the lumbar region. Its purpose is the 

 withdrawal of fluid. This fluid is usually thin 

 turbid pus containing flakes of fibrin. The turbidity 

 is due to great numbers of pus cells. These cells con- 

 tain the cocci of meningitis which are of the same 

 general size, shape, and arrangement as the gonococcus. 

 They are so like this coccus that one must be well 

 versed indeed to differentiate between the two without 

 a knowledge of the source of the specimen. The 

 meningitis cocci show a great variance in size and 

 shape within the same specimen, conditions not com- 

 mon with the gonococci. They also stain differently, 

 although both are not stained by the Gram method. 

 As is the case with gonococcus, they lie within the pro- 

 toplasm, but not in the nucleus. Given a turbid fluid 

 from a case suggestive of meningitis, it is possible to 

 make a diagnosis by finding these cocci. The cocci 

 may also be found in the blood. They develop agglu- 

 tinins whereby an additional assistance in diagnosis 

 may be given. 



The cocci are grown with moderate ease on labor- 

 atory media especially if they contain blood serum or 

 glucose. They grow best in the presence of oxygen, 

 at 37.5 C. or 98 R, but die rapidly if not put on 

 fresh food frequently. They will live a considerable 

 time in the ice-box, unlike the gonococcus. 



They are killed by heating to 50 C. or 122 F. for 

 ten minutes, by exposure to sunlight at once, and 



