1") 



fication of the inflaimnatory process. Thus, if we inocuhite ii rabbit in 

 the one ear with attenuated, in the other with virulent, anthrax, we find 

 that in the course of u few hours the latter ear exhibits much more 

 evident signs of inflammation than does the former ; it is much more 

 swollen, and there is greater congestion, and now if we examine the two 

 ears we find that in the latter we have to doal with a serous inflamma- 

 tion ; there has been great serous exudation. In the former there is less 

 mariied serous exudation, Ibut an extensive emigration of leucocytes ; the 

 inflammatory process is distinctly of a cellular nature.* Therefore, it 

 can safely he said that the condition of the iiumours as permitting or 

 preventing: the inflammatory reaction is not, in a large number of cases, 

 capable of explaining the phenomena attendant upon the production of 

 immunity and the spread of disease. 



Returniiig now to a more direct discussion of the problem before us, 

 we may say that the weight of evidence is against the assumption that 

 the body fluids in the refractory animal possess any but very feeble 

 bactericidal powers. The numerous instances that have been brought 

 forward of pathogenic micro-organisms retaining their vitality, luid even 

 their virulence for hours and days after they have been injected under 

 the skin or into the anterior chamber of the eye of definitely refractory 

 animals prevent any other conclusion. 



Yet it seems to me that tiiere is a class of cases in which there may 

 be development or exaltation of these bacteria-killing powers. The 

 instances referred to above are all of them cases in which purelj' local 

 inoculations have been made, or where very acute generalised infec- 

 tive process has been set up. It is the generalised infective processes 

 of slower progress that clinically possess the greatest interest. Let 

 us study pneumonia, for example. Tchistovitch found that in those 

 cases in which, in consequence of the strength of the virus, a fatal 

 endini;' was inevitable, there no increase occurred in the white cor- 

 puscles present in the blood jf where a less powerful virus was inoculated, 

 there tlie increase was most marked. Unless it so happens that within 

 the organism the dissolution of the white corpuscles is followed by 

 immediate destruction or inception by other cells of their bactericidal 

 substances, it seems eminently probable that here the blood plasma 

 and the lymph must gain bactericidal powers ; and I would go so far 

 as to suggest that the assumption that these bactericidal powers become 

 increased helps to explain the resolution of such disease by crisis. If the 

 strength of the virus and the reactive powers on the part of the organism 

 are such that the bacterial products induce a proliferation of leucocytes 



* Metchnikoff. BvUish Molkal Joimial, Jan. 31st, 1S91. 



t With this may bo compared Hildebiandt's observation that tlie febrile state induced by the 

 injection of lethal doses of various ferments is accompanied by a diminution in tlie number of 

 white corpuscles in the blood, a diminution which would seem to bo due to active destruction 

 of the corpuscles.— Kirc/iOi'/ff AvchU; Vol. OXXI., 1890, p. 1. 



