1907.] Substance in Serum ivhich influences Phagocytosis. 407 



Experiment. — A 24-hours' agar culture of a typhoid bacillus, recently 

 isolated from the blood of a patient, was emulsified in bouillon and diluted. 

 Into each of a series of small test-tubes there was introduced a quantity 

 -corresponding to 1/1000 of the whole bacterial mass. Serum was added in 

 varying amount, and the volume in each tube made the same by the addition 

 «of normal salt solution. A small volume of broth was also added to each 

 tube. 



These tubes were then placed in the incubator for three hours, after which 

 .a fixed volume was taken from each and plated. 



At the same time the various serum constituents were tested for 

 .sterility. 



Table IV 



Culture. 



i 



Fresh unheated 

 guinea-pig's serum. 



Normal rabbit's serum 



heated to 60° for 



20 minutes. 



Number of colonies 

 on agar plate. 



r 



ToPo of an a g ar 

 culture 1 day old of <{ 

 B. typhosus j 



L 



c.c. 

 0-5 

 0-25 



01 



0'5 

 0-25 



o-i 

 o-o 



c.c. 

 

 

 



1-0 

 10 

 1-0 

 1-0 



109,998 

 uncountable 

 uncountable 



4,365 



21,604 



uncountable 



uncountable 



This experiment shows that inactivated rabbit's serum is capable of being 

 reactivated by normal guinea-pig's serum, so that the combination of the two 

 is capable of producing a marked bacteriolytic effect in quantities which, 

 -acting apart, have little or no such action. Comparative tests with fresh 

 rabbit's serum and fresh guinea-pig's serum showed that the latter had much 

 less bacteriolytic action than the former, and the above experiment proves 

 ;that this difference is due to a deficiency of amboceptor. 



Employing the opsonin technique, a number of tests was performed with 

 the object of ascertaining how these two sera influenced the bacilli in 

 regard to phagocytosis. 



^Experiment. 





Phagocytic index. 



1 

 2 

 3 

 i 4 

 5 





0-2 



0-4 



5-7 



10-5 



15-6 





Guinea-pig's serum, fresh 



Rabbit's serum, fresh 



Rabbit's serum (60° for 20 minutes) + guinea-pig's serum, 

 fresh 



