Mode of Infection 405 



of the base of the brain. The inflammation extends, in monkeys, 

 into the membranes covering the olfactory lobes and along the dura 

 mater into the ethmoid plate and nasal mucosa. 



The nasal mucous membrane is found in many instances to be 

 inflamed and beset with hemorrhages. Smear preparations from 

 the nasal mucosa show many polymorphonuclear leukocytes con- 

 taining the cocci in a degenerated form. The cocci were not culti- 

 vated from the nasal exudates. 



Mode of Infection. — It is not known by what channels infection 

 with Diplococcus intracellularis meningitidis takes place. Weich- 

 selbaum supposed it might enter by the nasal, auditory, or other 

 passages, especially the nose, where he constantly found it, and the 

 more recent studies of Goodwin and ShoUy* have shown the organ- 

 isms to be of frequent occurrence in the nasal cavities of meningitis 

 patients as weU as occasionally in those associated with them. It 

 thus becomes evident that association with the diseased may lead 

 to the infection of the well, and that the cases should be isolated. 

 The same conclusions were reached by KoUe and Wassermann,t 

 who studied the nasal secretions of 112 healthy individuals, not 

 exposed to the disease, without finding- any cocci, but found them 

 in the nasopharynx of the father of a child suffering from the dis- 

 ease, and that of another child with suspicious symptoms. 



SteelJ has found what may be a variety of the meningococcus 

 in the simple posterior basic meningitis of infants. The organism 

 differs from that of Weichselbaum in having a greater longevity upon 

 culture-media, where it often lives as long as thirty days. It is 

 easily stained by methylene blue, but not by Gram's method. 

 Another simUar organism has been described by Elser and Huntoon. § 



Bacteriological Diagnosis. — ^In cases with the clinical symptoms 

 of meningitis, the bacteriological diagnosis is of great assistance in 

 determining the correctness of the diagnosis and the nature of the 

 infection. It is accomplished by means of the lumbar puncture 

 (vide supra) and the study of the cerebro-spinal fluid thus secured. 

 Normal cerebro-spinal fluid is clear, that in meningitis is cloudy. A 

 few cubic centimeters of the fluid can be used for culture and in- 

 oculation experiments of as many kinds as are deemed advisable. 

 The remainder is placed in a tube and whirled in a centrifuge. From 

 the sediment, smears are made upon slides and stained by various 

 methods, mcluding Gram's method. The occurrence of polymor- 

 phoriuclear leukocytes containing Gra,m-negaHve diplococci is diag- 

 nostic of cerebro-spinal meningitis. The occurrence of poly- 

 morphonuclear leukocytes and GTa,m.-positive diplococci may mean 

 pneumococcus or streptococcus infection. If the chief cells 



* "Journal of Infectious Diseases," 1906, Supplement No. 2, p. 21. 



t "Klinisches Jahrbuch," xv, 1906. 



t "Pediatrics," Nov. 15, 1898. 



§ "Journal of Medical Research," 1909, xx, 377. 



