GROWTH AND APPEARANCES OF COLONIES. 59 



Impression or "Klatseh" Preparations. In order to more 

 thoroughly study a certain colony and to make a permanent 

 specimen of the same, we press a clean cover-glass upon the 

 particular colony, and it adheres to the glass. It can then be 



FIG. 31. 



FIG. 32. 



Microscopic appearances 

 of colonies. 



Klatsch preparations. 



stained or examined so. The Germans give the name of 

 "Klatsch" to such preparations. Many beautiful pictures can 

 be so obtained. 



Fishing. To obtain and examine the individual members of 

 a particular colony the process of fishing, as it is called, is 

 resorted to. 



The colony having been placed under the field of the micro- 

 scope, a long platinum needle, the point slightly bent, is passed 

 between the lens and the plate so as to be visible through the 

 microscope, then turned downward until the colony is seen to 

 be disturbed, and the needle is dipped into the colony. This 

 procedure must be carefully done, lest a different colony be 

 disturbed than the one looked at, and an unknown or unwanted 

 germ obtained. 



After the needle has entered the particular colony, it is with- 

 drawn, and the material thus obtained is further examined by 

 staining and animal experimentation. The bacteria are then 

 again cultivated by inoculating fresh gelatine, making stab and 

 stroke cultures. 



