1904] Kole of Blood Fluids in connection ivith Phagocytosis. 141 



pestis, the Micrococcus melitensis, the Diplococcus pneumoniae of Fraenkel, 

 the Bacillus coli, the Bacillus dysenteries (Shiga), the Bacillus anthracis, 

 the Bacillus typhosus, and the Vibrio cholerce Asiatics. 



So far as we have gone, the Bacillus diphtherial and its congener the 

 Bacillus i xerosis have proved to be the only pathogenetic bacteria which 

 are insensible to this action of the blood fluids. 



Taking these experimental data in conjunction with other facts which 

 have been elicited by us, or as the case may be by one of us working 

 in connection with Captain F. Windsor,* I.M.S., with regard to the 

 bactericidal action exerted by human blood upon the various species 

 of pathogenetic micro-organisms, we may classify these bacteria in the 

 following categories : — 



(1) Bacteria which are eminently sensible to the bactericidal, bacteriolytic, 

 and opsonic action of normal human blood fluids. — The Bacillus typhosus 

 and the Vibrio cholerce Asiaticce. 



(2) Bacteria which are in some measure sensible to the bactericidal action 

 of the normal human blood fluids, and which are eminently sensible\to its opsonic 

 action. — The Bacillus coli and the Bacillus dysenteric. 



(3) Bacteria which are absolutely insensible to the bactericidal action of the 

 normal human blood fluids, but are eminently sensible to the opsonic action of 

 these fluids. — The Staphylococcus pyogenes, the Bacillus pestis, the Micro- 

 coccus melitensis, the Diplococcus pneumonice of Fraenkel. 



(4) Bacteria which are insensible both to the bactericidal and to the opsonic 

 action of human blood fl,uids.—Th.e Bacillus diphtherice and Bacillus 

 xerosis. 



It may be pointed out in conclusion that the demonstration fur- 

 nished above, that successful immunisation against the staphylococcus 

 pyogenes is dependent upon an elaboration of opsonins in the system 

 of the inoculated patient, suggests that successful immunisation against 

 plague and Malta fever, and we may add against streptococcal invasions, 

 may be likewise dependent upon the elaboration of opsonins. 



It will be manifest that if this is so, the determination of the opsonic 

 power of the blood is calculated to render services also in connection 

 with the testing of any therapeutic sera which may find an application 

 in connection with the disease. 



DESCRIPTION OF PLATE 3. 



Fig. 1. — White Blood Corpuscles digested with utiheated serum and culture of the 

 Bacillus typhosus for 15 minutes at 37° C. Shows, in the case of the 

 extra-cellular micro-organisms, complete spberulation and agglutination. 

 Many of the micro-organisms i;i the interior of the phagocyte are 

 unaltered with respect to their shape and staining reaction ; others — 

 presumably the later ingested micro-organisms — have undergone spheru- 

 lation. 



* ' Journ. of Hygiene,' vol. 1. 



