434 



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



" C." — Showed an intense degree of ingestion, and nearly all the free 

 organisms aggregated into clumps. 



"■ D." — Showed extreme agglutination and some degree of ingestion, but 



DO O O * 



not nearly so much as in " C," a rather curious result, probably due to 

 rapid agglutination preventing the full play of the leucocytes. 



A portion of each mixture washed in 1*5 per cent, saline, and freed from 

 leucocytes by the centrifuge, was planted out immediately, and in every 

 instance growth took place. The remaining portions of the mixtures were 

 shaken up with a large bulk of normal saline and incubated at 37° for two 

 hours, then lightly centrifuged. The upper portion was afterwards drawn off 

 and recentrifuged hard for a quarter of an hour, whilst the deposit was 

 planted out. Finally, the deposit of the recentrifuged upper portion, which 

 would contain free germs, was also planted out. The result is shown in the 

 following Table. 



Experiment 6. 



Mixture. 



Planted immediately 

 to show viability 

 of culture. 



Planted after 2 hours in normal saline. 



Leucocytie deposit. 



Free germ deposit. 



"A : ' 



Good growth 

 Good growth 

 Good growth 

 Good growth 



No growth 

 One or two colonies 

 Good growth 

 Good growth 



No growth. 



No growth. 

 Good growth. 

 Good growth. 



" B " 



" C " 



"D" 





At first sight this result was incomprehensible, since it appeared that 

 the immune serum of a patient (mixtures " C " and " D ") had no bacterio- 

 logical effect on his own germ or on a laboratory culture. Yet both were 

 apparently killed by the serum of a normal man. But consideration of the 

 foregoing experiments shows that in point of fact the result is quite 

 consistent. The explanation would appear to be as follows : — 



Mixture " A." — The old laboratory culture was taken up and killed by 

 the leucocytes whilst free organisms succumbed to the normal saline. 



Mixture " B." — This gave an identical result with Experiment 5 (q.v.). 

 All loose germs were killed by the normal saline, whilst from the leucocytie 

 deposit one or two colonies arose from odd germs, which had been ingested 

 and protected from the action of the saline by the leucocytes. 



Mixture " C." — Here the dominating factor in the situation seems to be 

 the agglutination, which, with an undiluted immune serum, may take place 

 in less than a minute. Under the influence of this serum, aggregations 

 of germs are taken up by the leucocytes, and, owing to the crowding of the 



