HISTORY OF MICROBIOLOGY. 5 



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 following 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 1860, Joseph Lister, an Edinburgh surgeon, 

 began to study the possible role of microbes in the infection of wounds. By 

 sterilizing his instruments, sponges, ligatures, 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. Lister's methods, suggested by the ideas of Pasteur, have 

 rendered possible the marvelous surgery of the present day, banished hos- 

 pital 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 fermenta- 

 tions of milk, such as souring, curdling, etc. He also confirmed the con- 

 clusion 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, F. 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 resistant 

 to heat than the rods from which they were derived. This fact was ob- 

 served in the well-known "hay bacillus" 



In 1871, 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 

 beautiful results by Ehrlich, Koch, Gram, and others. The staining 

 of microorganisms rendered it possible to obtain pictures of them by 

 photographic methods; the art of photomicrography developed thus 

 rapidly. 



In 1879, Miquel discovered bacteria which grew or developed at 

 temperatures between 65 and 75. He isolated them first from the waters 



