30 BAOTERtOLOGY. 



organisms in pure culture, to cultivate them indefinitely 

 under artificial conditions, to reproduce the lesions by 

 inoculation of these pure cultures into susceptible ani- 

 mals, and to continue the disease at will by continuous 

 inoculation from an infected to a healthy animal. By 

 the methods that he employed he demonstrated a series 

 of separate and distinct diseases that can be produced in 

 mice and rabbits by the injection of putrid substances 

 into their tissues. The disease known as septicsemia of 

 mice, likewise a disease characterized by progressive 

 abscess-formation, and pytemia and septicaemia of rab- 

 bits, were among the affections first produced by him in 

 this way. It was in the course of this work that the 

 Abbe system of substage condensing apparatus was first 

 used in bacteriology ; that the aniline dyes suggested by 

 Weigert were brought into general use ; that the isola- 

 tion and cultivation of bacteria in pure culture on solid 

 media were shown to be possible ; and that animals 

 were employed as a means of obtaining 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 Avill serve to indicate the lines alonsr 

 which the subject has developed. For a more detailed 

 account of the historical development of the work the 

 reader is referred to Loffler's instructive and enter- 

 taining Vorlesungen uher die gesehichtliche EntwicJcelung 

 der Lehre von den JBacterien, upon which I have drawn 

 largely in preparing the foregoing sketch. 



