178 LABORATORY METHODS OP 



What is meant by pathogenic, saprophytic, chromo- 

 genic and pyogenic bacteria? 



Are bacteria easily seen with the ordinary instru- 

 ment? 



At what temperature do they grow best? 

 Are all bacteria disease producers? 

 Are all bacteria chromogenic? 

 How did you fold the filter for nitration? 

 What is the advantage in this over the old way? 

 What medium did you make? 

 Are the principles the same? 



Take a large tube of water and sterilize over the 

 flame. 



How can you tell when the tube is sterilized? 

 What is the temperature of boiling water ? 

 Are the spores destroyed in the water if not, why 

 not? 



If we use a steam boiler can we destroy the spores? 

 If so, why can we? 



What is the name of the steam boiler that we use 

 in sterilizing cultures? 



Name all the agents used in sterilizing, as a class. 

 Name two methods of using the dry heat. 



