548 BACTERIOLOGY. 



fensive bodies to which Buchner has given the name 

 " alexins." ^ 



The first severe blow that Metchnikoff's theory of 

 phagocytosis received was given by Nuttall,^ in his 

 work upon the bactericidal property of the animal econ- 

 omy. In these experiments Nuttall demonstrated that 

 the destruction of virulent bacteria in the blood of 

 animals was not necessarily dependent upon the actual 

 presence of living leucocytes, but that the serum of the 

 blood when quite free from cellular elements possessed 

 this power to a degree equal to that of the blood 

 when all the constituent parts were present. In the 

 blood, as such, phagocytosis could be seen ; but, as a 

 rule, the bacteria observed within leucocytes presented 

 evidence of having undergone degenerative changes 

 before they had been taken up by the wandering 

 cells — i. e., the bacteria had evidently been injured or 

 killed by the fluids before they were attacked by the 

 phagocytes. 



Contrary to the beliefs in existence at the time, 

 Traube and Gscheidlen,' as far back as 1874, demon- 

 strated that considerable quantities of septic material 

 could be injected into the circulation of warm-blooded 

 animals without apparently any effect upon the animal. 

 Particularly was this the case with dogs. If they in- 

 jected into the circulation of a dog as much as 1.5 c.c. 

 of decomposing fluid, blood drawn from the animal 

 after from twenty-four to forty-eight hours showed no 

 special tendency to decompose, though it was kept 



1 See Hahn : Archiv fiir Hygiene, 1895, Bd. xxv. S. 105. 



2 Zeitschrift fur Hygiene, 1888, Bd. iv. 



* Jaliresb. der Schlesischen Ges. fiir Cultur., 1874 ; Jahr. iii. p. 

 179. 



