HISTORY OF MICROBIOLOGY 5 



vestigation as to the best means of combating the epidemic; and, after 

 several years of study, he found the organism causing the disease, 

 suggested remedies, and brought back wealth to the ruined com- 

 munities, but at the cost to himself of impaired health and partial 

 paralysis. 



Pasteur's results were very suggestive; and one outcome of his work 

 was that between 1870 and 1880 several important discoveries were 

 made by other investigators. Prior to the dates mentioned, the 

 mortality from blood poisoning, gangrene, and other infections follow- 

 ing operations was extremely high. Surgeons regarded such a result 

 as inevitable, and many agreed with the saying of Velpeau, that " the 

 prick of a pin is the open door to death;" but, in i860, Joseph Lister, 

 an Edinburgh surgeon, began to study the possible r61e of microbes in 

 the infection of wounds. By sterilizing his instruments, sponges, liga- 

 tures, etc., and using antiseptics, he was able to obtain such a high 

 percentage of recoveries that in two years he saved thirty-four patients 

 out of forty — a. percentage unheard of up to that time. Hence the 

 origin of the antiseptic and aseptic methods of surgery is traceable 

 to Lister's efforts. Lister's methods, suggested by the ideas of Pas- 

 teur, have rendered possible the marvelous surgery of the present day, 

 banished hospital gangrene, and robbed confinement of its terrors. 



To Lister must also be given the honor of devising the first practical 

 way of obtaining a pure culture of bacteria by means of high dilutions. 

 By using this method, Lister obtained some idea of the different fer- 

 mentations of milk, such as souring, curdling, etc. He also confirmed 

 the conclusion of Robert Hall (1874), that milk could be obtained 

 from the animal in a sterile condition, thus proving that the souring 

 of milk was caused by organisms from some external source. 



In 1872, r. Cohn's System of Classification, based on morphological 

 characters, appeared. He distinguished six genera — micrococcus, bac- 

 terium, bacillus, vibrio, spirillum, and spirochaete; four years later this 

 investigator made the important discovery of endospores (spores formed 

 within cells), and noticed that organisms in this state were more re- 

 sistant to heat than the rods from which they were derived. This fact 

 was observed in the well-known "hay bacillus." 



In 1 87 1, Weigert succeeded in staining bacteria with picro-carmine; 

 but it was not until 1876 that he used the aniline colors, or dyes, for this 

 purpose, and thus opened up a new field which was exploited with such 



