MILESTONES. 153 



3. Pasteur's studies of fermentations ; discovery of anaerobic organisms. 



4. Pasteur's studies of p^brine, iiacherie, anthrax, cliicken-cholera, and rabies. 



5. Cohn's system of classification. 



6. Cohn's discovery of endospore-bearing organisms resistant to heat. 



7. Introduction of anilin stains and photomicrograpliy. 



8. Tyndall's discontinuous moist sterilization. 



9. Leister's antiseptic surger}'. 



10. leister's dilution method for obtaining pure cultures. Ascribed also to 

 Naegeli. 



11. Miquel's discovery of thermophilic bacteria. 



12. Discover}'^ of root-tubercles of Legnminoste b)' Woronin, and subsequent 

 papers by Beyerinck, Hellriegel & Wilfarth, cl al. 



13. Discovery of bacterial diseases in plants b}' Burrill, Prillieux, and Wakker. 



14. General introduction of Koch's poured-plate method for obtaining pure 

 cultures. 



15. Koch's discovery of the "comma bacillus," the cause of Asiatic cholera. 



16. Paper on tuberculosis by Koch in Mitth. a. d. Kaiserlichen Gesundheitsamt, 

 Bd. II. 



17. Use of synthetic media, of pressure filters, of fermentation tubes, and of 

 other anaerobic apparatus. 



18. Introduction of apochromatic objectives. 



19. Eberth and Gaffky's discover}' of the bacillus of typhoid fever ; Nicolaier's 

 discover}' of the tetanus bacillus ; Ivoeffler & Schutz's discover}- of the bacillus of 

 glanders ; Salmon & Smith's discovery of the hog-cholera bacillus ; Yersin's and 

 Kitasato's independent discovery of the bacillus of plague ; Pfeiffer's discovery of 

 the organism causing influenza ; Shiga's discover}' of the cause of tropical dysenter}'. 



20. Winogradsky's stiidies of nitrifying organisms. 



21. Hansen's studies of fermentation, more especially yeasts. 



2 2. Duclaux's, Greene's, and Brown & Morris's study of enzymic actions. 



23. Study of toxines and anti-toxines ; general use of anti-diphtheritic serum. 



24. Migula's attempt to detennine the exact morphology of all known species. 



25. Discover}' of the cause of peripneumonia in cattle by Nocard & Roux ; 

 organism so minute as to be at the extreme limit of microscopic definition. 



26. Profound specialization, resulting in distinct classes of bacteriologists, e. £-., 

 animal and plant bacteriologists, milk bacteriologists, water bacteriologists, soil 

 bacteriologists ; and in special societies and journals, e.£-., those devoted exclusively 

 to the study of tuberculosis. 



Beyond this field, but of extreme pathological interest, and worked out by the 

 exact methods of the bacteriologist, are Laveran's discover}' of the protozoan causing 

 malarial fevers and Theobald Smith's discover}' of the protozoan causing the bovine 

 disease known as Texas fever, both parasites of the red blood-corpuscles. ]\Iore 

 recently it has developed that these are not rare types of disease. On the contrar}', 

 many virulent diseases of man and the lower animals are now known or believed 

 to be due to Tripanosomes or other Protozoans, and the literature on the subject 

 is becoming voluminous. 



