560 BACTERIOLOGY. 



of the disease by one or another of the modes of pro- 

 tective vaccination. 



As the phenomenon of phagocytosis could easily be 

 observed under the microscope, the plausibility of the 

 doctrine at once attracted many adherents, and Metschni- 

 koff's \>iews were everywhere accepted as the probable 

 explanation of the defensive mechanism of the body 

 against infection. 



In a little while, however, Fluegge, of Breslau, per- 

 ceiving the incompetency of both Chauveau's and Pas- 

 teur's doctrines, observing occasional inconsistencies in 

 Metschnikoif ? s teaching, and recalling certain significant 

 reactions of the blood that had appeared in the course 

 of experiments by Traube and Gscheidlen, by Fodor, 

 by Rauschenbach, and by Grohmann, determined to 

 subject the whole question to an experimental critical 

 review. 



To Nuttall, an American working in his laboratory, 

 was assigned the question of determining if the cell-free 

 blood, or the plasma, was, as had been suggested by 

 Grohmann, possessed of germ-destroying properties. 

 NuttalFs work resulted in a blow to Metschnikoff's doc- 

 trine that for a long time seemed to be fatal. He 

 demonstrated that certain virulent bacteria were ren- 

 dered incapable of development, incapable of infecting 

 susceptible animals, and, in short, killed by exposure to 

 the serum of animal blood free of all cellular elements. 

 These results naturally caused defections from the ranks 

 of MetschnikofF's followers, especially since Nuttall's 

 deductions were fully confirmed by many distinguished 

 experimenters. In consequence, for a number of years 

 after NuttalFs work, the cell-free fluids of the body 



