138 Chapter VI 



a longer or shorter period. When the activity of the phagocytes is 

 impeded by unfavourable influences, e.g. high temperature, they 

 exhibit a very feeble reaction, incapable of assuring to the frog that 

 immunity which, under normal conditions, it possesses. The con- 

 clusions I have just summarised have raised very lively opposition 

 from a large number of observers. Baumgarten^, with his pupils 

 Petruschky^ and Fahrenholtz^, have endeavoured to demonstrate that 

 phagocytosis plays no part in immunity and that the frogs resist 

 anthrax simply because the bacilli are incapable of maintaining 

 themselves alive in the fluids of this Batrachian. Nuttall*, of 

 Fliigge's school, also maintained that frogs resist anthrax owing to 

 the bactericidal power of their fluids. This view has been defended 

 by several other observers and appeared for some time to become 

 quite dominant. 



Nevertheless, it is possible to demonstrate that the plasmas of 

 the frog not only are not inimical to the life of the bacillus, but 

 serve as a good culture medium for it^. All that is necessary for the 

 demonstration of this fact is to introduce below the skin of frogs 

 [147] anthrax spores enclosed in a sac of reed pith, or simply enveloped in 

 a small piece of filter-paper. The plasma of the lymph sac at once 

 permeates the spores and allows them to germinate and produce 

 quite a generation of bacilli. But, as soon as the leucocytes pass 

 through the paper, they seize upon the young bacilli, digest them 

 in their substance and prevent their pathogenic action. The germi- 

 nation of the spores may take place even where they have been 

 introduced below the frog's skin without being protected in any way 

 whatever. But, under these conditions, only a certain number of the 

 spores germinate, the majority not having time to do so before the 

 arrival of the leucocytes. The small, very short bacilli which proceed 

 from the germinated spores, are, along with the spores that have 

 not germinated, soon ingested by the phagocytes. But, whilst the 

 rods are in the end digested within these cells, the ingested spores 

 remain intact for a very long time : they do not germinate, but they 

 are not destroyed and retain their vitality indefinitely, in spite of 



1 CentralU.f. klin. Med., Bonn, 1888, S. 616. 



* " Untersuch. iiber d. Immunitat d. Frosches gegen Milzbrand," Ziegler's Beitr. 

 z.path. Anat, Jena, 1888, Bd. in, S. 357. 



3 "Beitrage z. Kritik der Metschnikoff'schen Phagocytenlehre," Inaug. Diss., 

 Konigsberg, 1889. 



* Ztschr.f. Hyg., Leipzig, 1888, Bd. iv, S. 353. 



^ Virchow'8 Archie, Berlin, 1888, Bd. cxiv, 8. 466. 



