180 LABORATORY METHODS OP 



Method: Put some water in the water-bath; put 

 the tube of culture in it, and heat to 56 degrees C. ; let 

 it remain for fifteen minutes. 



Inoculate a second tube from this one, and store in 

 your locker. Note the tube next day and see if there is 

 any growth in the tube. If not, the thermal death-point 

 is 56 degrees C. This method is the one we follow 

 at all times. 



Learn the theory of reproduction of bacteria. Note 

 the color on the board which represents the stained 

 germ and the stained spore. 



tfOOD SUPPLY. 



The medium on which bacteria grows is termed 

 food. We are to determine the best food on which 

 they grow. The best ones are bouillon, agar-agar and 

 gelatin. In order to determine the reactions of the 

 medium after the germs have been growing on the 

 medium, it must be of a composition the same as that 

 of the tissues and juices of the body, or the same as 

 that of the dead organic bodies. This we attempt to 

 do when we make the different media. The properties 

 of media which must be observed are clearness 'and so- 

 lidity. The characteristic growth of the culture is ob- 

 served on solid media. 



