168 BACTERIOLOGY FOR NURSES 



against Group II, but it has not had the same success as that pre- 

 pared against Group I. Group IV is not really a group but an 

 assembling together of all the remaining isolated strains. 



Vaccines have been employed for the production of active 

 immunity as a prophylactic measure; their curative value is 

 doubtful in a disease so acute and relatively brief. 



Relation of Pneumococci and Streptococci. A group of cocci 

 have frequently been found in various diseased conditions such 

 as pneumonia and meningitis, which besides possessing a volu- 

 minous capsule are surrounded by a viscous substance which 

 gives a slimy consistency to cultures and to exudates. So closely 

 do they appear to be related both to the pneumococci and to the 

 streptococci that it is difficult to determine with which they should 

 be placed. It has been suggested that they be divided into two 

 groups: (1) pneumococcus mucosus, which resembles the true 

 pneumococcus in that it is non-hemolytic on blood agar, is soluble 

 in bile, gives rise to acid and coagulation in serum inulin medium, 

 and is very pathogenic to white mice ; on the other hand, it forms 

 much larger colonies than the pneumococcus, and the individual 

 cocci tend to be less pointed. Recent investigators regard it as 

 Group III in the pneumococcus classification. (2) Streptococcus 

 mucosus is usually non-hemolytic, is not soluble in bile, and does 

 not ferment inulin; the colonies are less transparent, the in- 

 dividual organisms are round and occur in chains. Thus while 

 the pneumococcus mucosus is practically a true pneumococcus 

 the streptococcus mucosus appears to form a connecting link 

 between it and the streptococci. 



MENINGOCOCCUS 



Inflammation of the membranes surrounding the brain and 

 spinal cord may be caused by several different organisms; it 

 may occur as a primary or secondary infection. As a secondary 

 infection it not infrequently occurs during pneumonia as a result 

 of the pneumococcus being carried to the meninges by the blood 

 stream; sometimes the tubercle bacillus is the invader. In- 



