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Drs. C. Shearer and H. W. Crowe. 



ingestion on the part of the phagocytes. At the same time it also becomes 

 weaker, and may succumb to the lethal action of the serum or of the serum 

 and the leucocytes combined. Thus the examination of the leucocytes when 

 tested with an enfeebled throat strain shows them to be gorged with 

 " shades " and poorly stained cocci. The substance of the leucocytes is 

 vacuolated, suggesting the complete digestion of some of the germs taken 

 up. This appearance is never seen in recently isolated spinal strains even 

 when ingestion of the germs by the phagocytes is obtained with an immune 

 serum. 



If it were possible to trace a case of disease to a certain " carrier," 

 eliminating any other possible source of infection, we ought to be able to 

 demonstrate phagocytosis of the organism when isolated from the " carrier," 

 although no ingestion on the part of the phagocytes would be observed in 

 the same germ when isolated from the patient. 



We were fortunate in coming across such a case, where the course of 

 infection seemed to be beyond doubt. A patient developed cerebro-spinal 

 fever after he had been in hospital a few days. None of his hospital 

 contacts were " carriers " of the meningococcus. On investigating the camp 

 from which he came we found one " carrier " with whom he had been in close 

 contact in the same hut. In the presence of normal serum the germ from 

 this man's throat was readily attacked by the phagocytes to a considerable 

 degree. No ingestion on the part of the phagocytes could be demonstrated, 

 however, after the passage of the germ through the patient. These strains, 

 both spinal and nasal, we presume were the same, as they both behaved 

 identically when tested with Gordon's monovalent serum Type 2. In this 

 instance, then, it is hard to avoid believing that the man was infected from 

 this " carrier," and it is interesting in the light of our experiments to note that 

 the germ at the time of infection in this case was rapidly attacked by the 

 phagocytes in the presence of normal serum. 



Summary. 



As the result of the foregoing experiments we think we have obtained 

 good evidence for thinking that under certain conditions the meningo- 

 coccus can be taken up by the leucocytes but not killed by them. In the 

 case of freshly isolated strains we have seen that the leucocytes will not take 

 them up at first. With old laboratory cultures, on the other hand, ingestion 

 on the part of the phagocytes takes place with great rapidity. In a short 

 time the germs are killed and completely digested by the leucocytes. 



This happens also with the majority of the nasal strains we have examined 

 from chronic " carriers " although they show greait individual differences. 



