178 ESSENTIALS OF BACTERIOLOGY 



Colonies. Circular discs, whitish, almost transparent, mar- 

 gins, smooth. 



Stain. With basic anilin. Gram negative. Jenner's 

 blood-stain and Neisser stain best for spinal fluid specimens. 

 Loffler's alkaline methylene-blue a good stain. 



Resistance. Organisms very perishable one to three days. 

 Apparently destroyed by a self-elaborated ferment. Sun- 

 light destroys in a few hours. 



Pathogenesis. Causes epidemic cerebrospinal fever, prob- 

 ably by infection through the nasopharynx; the organism is 

 found in the spinal fluid and in other inflammatory exudates, 

 and can be seen in fluid obtained by lumbar puncture. 



Ordinary laboratory animals immune, but Flexner has 

 succeeded in inoculating monkeys. 



Agglutination. On the fourth day; in dilution of i : 50 

 agglutination is had. 



By the use of large quantities of meningococci injected into 

 a horse agglutinins, opsonins, and specific immune bodies 

 (amboceptor) can be produced. 



Protective Serum. Flexner has been able to obtain an anti- 

 toxin from monkey serum that has therapeutic properties in 

 man. Such an antiserum, when injected directly into the 

 spinal canal, has a curative action, destroying the cocci. 



Bacterial Diagnosis. By means of lumbar puncture the 

 spinal fluid is obtained and allowed to settle. Smears made 

 from sediment. Examined for bacteria. 



Gram-positive organisms are either pneumococci, strepto- 

 cocci, or staphylococci. 



Meningococcus is Gram negative and within the leukocytes, 

 and can be readily grown on blood-serum. If such an or- 

 ganism is present, the disease is undoubtedly cerebrospinal 

 meningitis. 



Bacillus of Soft Chancre, Chancroid (Ducrey-Unna, 

 1889). A diplobacillus which is specific has been described 

 by Ducrey as obtained from the secretion and in the depth 

 and margins of the chancroid. Unna's bacillus is narrower 

 and unbroken in the center (Fig. 88). 



