136 



Dr. A. E. Wright and Capt. S. E Douglas. [Jan. 11, 



B. 



S. R. D.'s heated serum 3 vols. 



S. R. D.'s washed corpuscles 3 ,, 



Suspension of the Bacillus anthracis 1 vol. 



Here there were practically no signs of phagocytosis. The cells were 

 everywhere empty, and they had not drawn themselves into intimate 

 contact with the anthrax threads (fig. 6). 



Experiment 2. 

 A. 



A. E. W.'s unheated serum 2 vols. 



S. R. D.'s washed corpuscles 2 ,, 



Broth culture of anthrax 1 vol. 



Phagocytic index (36 P.W.B.C.), 2*4 (approximate only). 



B. 



A. E. W.'s heated serum 2 vols. 



S. R. D.'s washed corpuscles 2 ,, 



Broth culture of anthrax 1 vol. 



Phagocytic index (100 P.W.B.C.), 0. 



Opsonic Power of Human Blood in its Eelation to the 

 Bacillus typhosus and the Cholera Vibrio. 



It is well known that human blood exerts a very considerable 

 bactericidal power upon cultures of the Bacillus typhosus and of the 

 cholera vibrio. The destructive effect in question manifests itself to 

 microscopical observation in the form of very profound morphological 

 changes which come under observation in cultures which have been 

 digested with unheated. serum. The bacteria in such cultures, after 

 undergoing agglutination and spherulation, swell up and lose their 

 chemical affinity for anilin dyes. Finally they are completely 

 dissolved. 



It is manifest that where disintegrative changes of this kind are 

 occurring under the influence of the serum, opsonic effects will be more 

 or less thrust into the background. These last will, in the case 

 of phagocytic experiments conducted with unheated serum, be masked, 

 on the one hand, by the fact that there will be fewer bacteria available 

 for phagocytosis, and on the other hand by the fact that intracellular 

 disintegration will, it may be presumed, be more rapid in the case 

 where the serum has already exerted a disintegrative effect on the 

 bacteria anterior to their ingestion. 



Lastly, ingested bacteria which have lost their characteristic chemical 

 affinity for their stain may readily escape enumeration. 



