310 APPLICATION OF METHODS OF BACTERIOLOGY 



Determine if the maximum thermometer indicates a 

 temperature of 100° C. at the centre of a moist bundle in 

 the same way as when a dry bundle was employed. 



To about 50 c.c. of bouillon add about 1 gram of chopped 

 hay, and allow it to stand in a warm place for twenty-four 

 hours. At the end of this time it will be found to contain 

 a great variety of organisms. Continue the observation, 

 and ultimately a pellicle will be seen to form on the surface 

 of the fluid. This pellicle is made up of rods which grow 

 as long threads in parallel strands. In many of these rods 

 glistening spores will be seen. After thoroughly shaking, 

 filter the mass through a fine cloth to remove coarser 

 particles. 



Pour into each of several test-tubes about 10 c.c. of the 

 filtrate. Allow one tube to remain undisturbed in a warm 

 place. Place another in the steam sterilizer for five minutes; 

 a third for ten minutes; a fourth for one-half hour; a fifth 

 for one hour. 



At the end of each of these exposures inoculate a tube of 

 sterilized bouillon from each tube. Likewise make a set 

 of plates or Esmarch tubes upon both gelatin and agar-agar 

 from each tube, and note the results. At the same time 

 prepare a set of plates or Esmarch tubes on agar-agar and 

 on gelatin from the tube which has not been exposed to the 

 action of the steam. 



The plates or tubes from the unmolested tube will present 

 colonies of a variety of organisms; separate and study these. 



Those from the tube which has been sterilized for five 

 minutes will present colonies in moderate numbers; but, as 

 a rule, they will represent but a single organism. Study this 

 organism in pure cultures. 



The same may be predicted for the tube which has been 



