Highlights in the History of Microbiology 49 



the etiology of cholera epidemics after his studies in Calcutta, 

 India, where the disease was endemic. The Emperor of Germany 

 bestowed the Order of the Crown, with star, on Robert Koch for 

 his brilliant discoveries. His laboratories in Berlin became the 

 focal point for training laboratory technicians. The germ theory 

 of disease was now firmly established, and Koch, together with his 

 ever-widening circle of trained personnel, began a chain reaction 

 of discoveries. Once we knew the cause of disease, isolated the 

 germ, and found ways to destroy it, we were able to cut out a link 

 in the chain of the progress of disease, giving us the greatest 

 control in the spread of diseases of man in recorded history. What 

 has been accomplished has already been reviewed in the intro- 

 ductory chapter under the discussion of life expectancy since the 

 turn of the twentieth century. 



Pasteur had not been idle while Koch and his disciples were 

 busy perfecting new technics, and Pasteur's armouncements also 

 began to stir the imagination of men. Lord Lister carried out his 

 first aseptic surgery with the help of a fine mist of carbolic acid 

 playing on the field of operation, after soaking his instruments in 

 the same solution to destroy these, germs that Pasteur and Tyndall 

 had so conclusively demonstrated were present in the air. This is 

 the foundation of modern surgical procedures, based today upon a 

 combination of asepsis and disinfection. 



We can divide this history of microbiology into three periods. 

 People do not always agree with the limiting dates of these periods, 

 but in general we can say that until the year 1850 most micro- 

 biology was purely speculative in nature. From 1850 until about 

 1900 the important fundamental discoveries were made, preparing 

 for the so-called modern era from 1900 to the present. Too often 

 students of this science feel that everything has been discovered; 

 nothing remains to be done. This may be the tendency of some 

 individuals in the twilight of their lives, but any real student of 

 bacteriology can hardly read a single printed page in a research 

 journal, without realizing that much remains to be done. If one 

 thinks in terms of bacterial diseases, we will have to agree that 

 many of the former scourges of mankind have been fairly-well 



