The Role of the Phagocyte in Cerebrospinal Meningitis. 437 



In the intermediate stage between the fresh spinal condition and the 

 naso-pharyngeal state, it can be shown experimentally that they are taken 

 up, but not killed, by the leucocytes. They can be recovered from them 

 after a period of 24 or 48, or even 60 hours, and grown on artificial media. 

 If we can believe they behave similarly within the body, then we can 

 understand how they might be carried into the spinal canal and there set up 

 infection. 



It might also explain why direct infection (apart from the "carrier"), seldom, 

 if ever, takes place in cerebro-spinal fever ; that is from patient to patient, 

 attendant, or physician, etc., the phagocytes refusing to take iip the germs in 

 their virulent condition. In the " carrier," on the other hand, in the majority 

 of instances, the germs have lost their virulence so completely that they are 

 taken up and immediately killed and digested. 



In conclusion : if the method of infection is by leucocytic conveyance, 

 then the reason why direct infection is so uncommon is clear. The virulent 

 organism is unsusceptible of being attacked by the phagocytes. The longer 

 the germs grow in the " carrier " throat, the more easily will they be 

 ingested until a time is reached, when, on ingestion, they are also destroyed. 

 Somewhere between these two extremes, infection may produce the disease. 

 The organism is sufficiently weakened to give in to the leucocytic attack, but 

 not to lose its life in the battle. Should infection occur at this point, the 

 leucocytes will pick them up from the mucous membrane of the naso-phaiynx. 

 and in the course of their wanderings will sometimes carry them into the 

 spinal canal. There the liberated organisms will set up the disease, at the 

 same time re-acquiring the power of resisting the attacks of the leucocytes 

 in the presence of normal serum. 



Appendix. 



The important part played by virulent non-ingestible strains of the 

 meningococcus, as compared with virulent indigestible ones, in the light 

 of the foregoing experiments, renders necessary some consideration of 

 Eosenow's* remarkable results with virulent and non-virulent strains of 

 the pneumococcus. 



Eosenow has brought forward certain experiments to show : first, that a 

 non-virulent pneumococcus strain does not absorb opsonin from a normal 

 serum, and that it is always non-ingestible; secondly, if well washed it 

 will become indigestible. He considers these properties to be brought 

 about through the possession on the part of the virulent cocci, of a specific 



* Eosenow, ' Journ. Inf. Dis.,' vol. 4 (1907). 

 VOL. LXXXIX. — B. 2 



