584 BA CTERIOLOG Y. 



substances that are thrown into the circulating blood, 

 and which, in part at least, comprise the defensive bodies 

 to which Buchner has given the name " alexins." 1 



The first severe blow that Metchnikoff's theory of 

 phagocytosis received was given by Nuttall, 2 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 be- 

 fore 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. 



There is a bit of interesting history leading up to the 

 idea on which Nuttall worked. Contrary to the beliefs in 

 existence at the time, Traube and Gscheidlen, 3 as far back 

 as 1874, demonstrated that considerable quantities of sep- 

 tic 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 injected into the circulation of a dog as much as 

 1.5 c.c. of decomposing fluid, blood drawn from the ani- 

 mal after from twenty-four to forty-eight hours showed 

 no special tendency to decompose, though it was kept 



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



2 Zeitschrift fur Hygiene, 1888, Bd. iv. 



3 Jahresb. der Schlesischen Ges. fur Cultur., 1874 ; Jahr. iii. p. 179. 



