216 THE ACUTE PNEUMONIAS 



canal marked congestion and inflammatory change in the 

 nasal mucous membrane followed, and in this position he was 

 able to find a Gram-negative diplococcus ; he was, however, 

 unable to recover the diplococcus intracellularis in culture from 

 this situation. These results would seem to indicate that the 

 organism might spread from the brain to the nasal cavity, but if 

 this be so, it also follows that an extension may take place in 

 the reverse direction. On the whole the evidence at present 

 tends to show that the entrance of the organism into the body 

 is by the naso-pharynx, and that this usually results by 

 inhalation of the organism distributed in fine particles of 

 expectoration, etc. In fact, as regards the mode and conditions 

 of infection, an analogy would appear to hold between this 

 disease and influenza. 



Apart from the epidemic form of the disease, cases of sporadic 

 nature also occur, in which the lesions are of the same nature, 

 and in which the diplococcus intracellularis is present. The 

 facts stated would indicate that the origin and spread of the 

 disease in the epidemic form depend on certain conditions which 

 produce an increased virulence of the organism. We are, however, 

 as yet entirely ignorant as to what these conditions may be. In 

 simple posterior basal meningitis in children, a diplococcus is 

 present, as described by Still, which has the same microscopic 

 and cultural characters as the diplococcus intracellularis ; it has 

 been regarded as probably an attenuated variety of the latter. 

 Recently, however, Houston and Rankin have found that the 

 serum of a patient suffering from epidemic meningitis does not 

 exert the same opsonic and agglutinative effects on the diplococcus 

 of basal meningitis as on the diplococcus intracellularis; and 

 this result points to the two organisms being distinct, though 

 closely allied, species. 



An agglutination reaction towards the diplococcus intracellu- 

 laris is given by the serum of patients suffering from the disease, 

 where life is prolonged for a sufficient length of time, but the 

 degree of the reaction does not possess much clinical significance. 

 It usually appears about the fourth day, when the serum may 

 give a positive reaction in a dilution of 1 : 50 ; at a later stage 

 it has been observed in so great a dilution as 1 : 1000. There is 

 thus no doubt that anti-substances are produced in epidemic 

 meningitis as in other diseases, and this is also found to be the 

 case on inoculation of animals with pure cultures. Attempts 

 had been made to obtain an anti-serum, and a certain measure of 

 success has been obtained so far as experimental results are 

 concerned. Flexner obtained such a serum from a goat, and 



