406 Mr. G. Dean. Enquiry into the Nature of the [Apr. 23. 



Table III. — Average Number of Bacilli Ingested per Leucocyte. 



Experiment 

 number. 



• 

 A. 



Normal serum fresh. 



Dil. 1 : 30, ultimate 



dil. 1 : 90. 



B. 



Anti-dysentery serum heated to 



60° C. for 20 minutes. 

 Dil. 1 : 100, ultimate dil. 1 : 300. 



C. 



A mixed with B. 



(1) 

 (2) 

 (3) 

 (4) 



1-7 

 0-5 



5-6 

 2-5 



1-0 



1-2 

 4'3 

 1-3 



7-5 



5-9 



16-1 



9-0 



Total 



10-3 



7, 



38-5 



Mean of averages 



2-5 



1-9 



9*6 



If the effect produced by the combined action of the normal fresh serum 

 and the immune heated serum were merely additive, the calculated value 

 should be 4'2, whereas the experimental value is 9*6. Taking into con- 

 sideration the results obtained in the experiments upon the influence of 

 dilution, we must assume that the mixture containing the higher serum 

 concentrations should have given a lower count even than 4"2, whereas, by 

 experiment, a count of 9 - 6 is obtained. Another factor, therefore, must be at 

 work in the production of this result, in all probability the complementary of 

 the immune serum by the fresh normal serum. 



Experiments with the Typhoid Bacillus and the normal Sera of the Guinea-pig 



and of the Babbit. 



Certain normal sera have been very thoroughly investigated for the 

 presence of amboceptor and complement in connection with bacteriolysis. It 

 seemed of interest to examine some of these for sensitising and complementing 

 action from the standpoint of phagocytosis. 



If a like relation is proved to exist, it will be at least an indication that the 

 substances which prepare the microbes on the one hand for extracellular 

 bacteriolysis, and on the other hand for phagocytosis, are identical, and that 

 free complement, while an essential factor only in the former process, yet 

 plays in the latter also an important, if secondary, role. 



The sera of the rabbit and guinea-pig, which have been investigated by 

 Wechsberg (1902) and others for amboceptor and complement action in 

 .relation to the bacteriolysis of the typhoid bacillus, offer excellent material 

 .for a comparative study of the two processes. 



The following experiment, which is a repetition and confirmation of an 

 experiment of Wechsberg, shows how the matter stands for bacteriolysis in 

 .the case of the guinea-pig and of the rabbit. 



