XXI] PATHOGENIC ORGANISMS 561 



phagocytosis is this : after the introduction of a particular 

 microbe, say bacillus anthracis, into the tissue, say the 

 dorsal lymph-sac of a normal frog, the ensuing leucocytosis 

 develops comparatively slowly and late ; if, for instance, a 

 dose of bacillus anthracis or its spores, or of bacillus prodi- 

 giosus, be injected into the dorsal lymph-sac, numbers of 

 these bacilli or the spores are rapidly absorbed into the 

 blood of the general circulation, and can be there demon- 

 strated by culture already ten minutes after the injection 

 (Klein). If the animal be killed ten, thirty minutes, two 

 or six hours after injection, the heart opened and a drop of 

 blood rubbed over the slanting surface of gelatin or Agar 

 respectively, and incubated, twenty-four to forty-eight hours 

 later a large number of typical colonies of bacillus anthracis 

 or prodigiosus respectively will be found on the gelatine or 

 Agar respectively. 



The " fight " ensuing between the bacilli and their spores 

 introduced into the dor-sal lymph-sac and the leucocytes, 

 which are supposed to rush to the seat of the battle, i.e. the 

 dorsal lymph-sac, must be considered a very hollow affair, 

 if before the defending army can reach the seat of war a 

 host of the invaders have already escaped all over the 

 couritry as it were. Besides, before the defenders can 

 amass their legions at the seat of battle, many hours must 

 elapse, and it has been shown that many of the invaders 

 are already dead in the lymph-sac before there is any sign 

 of attack by the defenders, any sign of phagocytosis (Fischel, 

 Fortschr. d. Med. ix. 2), and that the lymph of the lymph-sac 

 free of leucocytes destroys the bacilli (Sanarelli, Centr.f. 

 Bakt. und Parasit. ix. 14). More than that, Kanthack and 

 Hardy show conclusively that prior to any phagocytosis, i.e. 

 prior to the accumulation of leucocytes which are able to take 

 up the microbes, the cells which are present or which aggre- 



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