538 PATHOGENIC MICROORGANISMS 



rapidly dies out in dust, or even in sputum, under conditions of 

 low temperature, deficient moisture and competition with other 

 microorganisms. As far as we know, it is not carried by any of 

 the domestic animals and, therefore, the origin of infection lies in 

 the secretions of cases and of carriers. The microorganisms are 

 found in the noses and throats of the sick, sometimes in the secre- 

 tions of the eye where a meningococcus conjunctivitis may exist. 

 With the secretions of these mucous membranes it reaches the outer 

 world. The meningococci may be present in cases for a long time 

 after convalescence, and, as we know, they are present in a consider- 

 able percentage of people who have never had meningitis, with whose 

 secretions the organisms may be constantly transferred to contacts. 

 Transmission probably occurs by close contact between carrier or case 

 and new host, through the nasopharynx, where the organisms lodge and 

 multiply. From this lodgment they pass into the meninges, either 

 directly along the lymphatic channels to the base of the skull, or 

 perhaps indirectly by way of the general circulation. The former 

 route is the one favored by most observers. However, during the 

 early periods of the war, a few cases were reported by British 

 clinicians, in which blood culture was positive before symptoms of 

 meningitis had developed, and during these army epidemics, we, 

 as well as others, saw occasional cases of general meningococcus 

 septicemia which died without ever developing meningitis. In- 

 cidentally, it may be stated that these cases develop a generalized 

 rash which, in some of its stages, is not unlike that of typhus fever. 

 The writer recalls a case in which he made a probable diagnosis of 

 typhus fever which in the light of subsequent experience seems to 

 him to have possibly been a case of meningococcus septicemia. 

 Positive blood culture in such cases will differentiate between the 

 two diseases. Herrick 47 studied this phase of the problem at Camp 

 Jackson in 1918 with great care, and came to the conclusion that 

 in 50 per cent of the cases early blood culture will reveal general 

 infection before clinical evidences of meningeal invasion are ap- 

 parent. This observation is of the greatest importance, indicating 

 the desirability of early blood culture work for doubtful diagnosis, 

 and also throwing light upon the wisdom of intravenous serum 

 therapy combined with the intraspinous injections. 



Infection of a healthy individual from a case is of very rare 



41 llerrick, Arch. Inter. Med., 21, 1918, 541. 



