12 APPLIED BACTERIOLOGY FOR NURSES 



reason why some two hundred years elapsed between 

 the discovery of bacteria by Leeuwenhoek and the 

 recognition of their role in the production of disease, we 

 find that this was due to the mechanical imperfections 

 of the microscope and to the difficulties surrounding 

 the isolation and cultivation of these minute organisms. 

 Thanks to the genius of Pasteur and of Koch these 

 difficulties were successfully overcome, and the founda- 

 tion of modern bacteriology securely laid. Prior to 

 this, however, Lister, who had carefully followed 

 Pasteur's work on fermentation, became convinced that 

 infections following surgical operations were due to the 

 introduction of bacteria. He accordingly devised what 

 is known as "antiseptic surgery," whereby it was sought 

 to kill all the germs which might gain access to the wound 

 at the time of operation and at the subsequent dressings, 

 and at once caused an almost complete disappearance 

 of surgical infections. 



Following the splendid work of Pasteur and Koch 

 progress in bacteriology was marvelously rapid. The 

 bacillus of typhoid fever was discovered by Eberth in 

 1880; the bacillus of tuberculosis, by Koch in 1882; the 

 spirillum of cholera, by Koch in 1884; the diphtheria 

 bacillus, by Klebs and Loffler in 1883; the bacillus of 

 lockjaw, by Kitasato in 1889, and so on. 



We have already mentioned that following Leeuwen- 

 hoek's discovery of bacteria these organisms were held 

 to be the cause of a great variety of diseases. In facti 

 for some time people seemed "bacteria mad." We now 

 know that bacteria are associated only with a certain 

 group of diseases which we call infectious diseases. An 

 infectious disease is caused by a living germ, though 



