XXI] PATHOGENIC ORGANISMS 569 



antagonistic action vested in these fluids, on the one hand, 

 as to their power of being nutritive, and, on the other, as to 

 being germicidal \ the first depends on materials no longer 

 living, e.g., dissolved or broken-down blood-corpuscles, the 

 latter on the " living '' or " active '' condition of albumen. 

 Buchner shows that the circulating blood possesses the 

 germicidal property in a higher degree than blood after 

 removal from the body : evidently the former contains in a 

 much smaller degree the particular nutritive elements than 

 the latter, which of course contains the products of the dead 

 or broken-down blood-corpuscles. Buchner further shows 

 that the germicidal power of the blood is not directly 

 dependent on the leucocytes, and further that it depends on 

 the albumen present in the plasma or serum, as long as this is 

 in combination with salt, or, as he terms it, is in an " active " 

 state. Plasma or serum free of cells acts germicidally ; if 

 from it, by dialysis, the salt is removed, it loses its germi- 

 cidal power ; the salts of the plasma or serum themselves 

 possess, however, no germicidal power. Lubarsch {Fort- 

 sclmtte d. Medizin, Bd. viii., No. 17) thinks it probable 

 that the germicidal action and inhibitive power of the living 

 tissues may in a large measure depend on the chemical activity 

 of the tissue cells, that is, on chemical substances excreted 

 or produced by the cells ; hence the battle against bacteria 

 is essentially of a bio-chemical nature, as has been ably 

 demonstrated by Petruschki in a series of papers. 



The substance or substances to which the plasma, serum, 

 or tissue juices owe their germicidal power are called by 

 Buchner Alexities [aXeietv, to protect). It must however be 

 clear that, whatever the exact nature of these alexines, they 

 cannot be the same, either in all animals or for the different 

 pathogenic bacteria. The alexines against anthrax in an in- 

 susceptible animal, e.g., rat, frog, cannot be the same as the 



