26 SA OTEBIOL OOY. 



that by proper methods it is possible to isolate these 

 organisms in pure culture, to cultivate them indefinitely, 

 to reproduce the conditions by inoculation of these pure 

 cultures into susceptible animals, and, by continuous 

 inoculation from an infected to a healthy animal, to 

 continue the disease at will. By the methods that he 

 employed he demonstrated a series of separate and dis- 

 tinct diseases that can be produced in mice and rabbits 

 by the injection into their tissues of putrid substances. 

 The disease known as septicaemia of mice; also a disease 

 characterized by progressive abscess-formation ; and 

 pysemia and septicaemia of rabbits, are among the affec- 

 tions produced by him in this way. It was in the course 

 of this work that the Abbe system of substage condens- 

 ing apparatus was first used in bacteriology; that the 

 aniline dyes suggested by Weigert were brought into 

 general use; that the isolation and cultivation of bacteria 

 in pure culture on solid media were shown to be possible; 

 and that animals were employed as a means of obtain- 

 ing from mixtures pure cultures of pathogenic bacteria. 

 With the bounteous harvest of original and important 

 suggestions that was reaped from Koch's classical series 

 of investigations bacteriology reached an epoch in its 

 development, and at this period modern bacteriology 

 may justly be said to have had its birth. 



Note. — I have presented only the most prominent 

 investigations that will serve to indicate the lines along 

 which the subject has developed. For a more detailed 

 account of the historical development of the work the 

 reader is referred to Loeffler's Vorlesungen iiber die 

 gesehiohtliche Entwickelung der Lehre von den Bacterien, 

 upon which I have draAvn largely in preparing the fore- 

 going sketch. 



