HISTORIC DEVELOPMENT OF IMMUNOLOGY 15 



ber 1877 his methods of fixing and drying bac- 

 terial films on cover slips by staining them with 

 anilin dyes. In 1881 he produced his important 

 paper on the method of obtaining pure cultures 

 of microorganisms by the poured-plate method. 

 Klebs (1834-1913) is with Pasteur, perhaps, the 

 most important precursor in the bacterial the- 

 ory of infection. He saw the diphtheria ba- 

 cillus before Loeffler (1883) and made solid cul- 

 tures of bacteria before Koch. Loeffler (1852-) 

 discovered the bacillus of glanders (1882) and 

 established the causal relation of the diphtheria 

 bacillus (1884). 



Immunisation Meanwhile, real light was 

 thrown upon the unknown problems of immu- 

 nity by Metchnikoif (1845-), the eminent Rus- 

 sian biologist who, in his studies on inflamma- 

 tion, showed (1883) that certain of the tissue- 

 cells and particularly the polymorphonuclear 

 leukocytes were active in the defence of the 

 human body by absorbing the invading bacteria 

 (phagocytosis). His theory of phagocytosis re- 

 mains a demonstrable fact and establishes the 

 important role of cells in the processes of im- 

 munity. This process in the hands of Sir Aim- 

 roth Wright and others was utilized in develop- 



