172 BACTERIOLOGY. 



time that is required for the expulsion of the air from 

 the meshes of the material cannot be given. 



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 one gramme 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 a pellicle will be seen to form on 

 the surface of the fluid. This pellicle will be 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 unmolested in 

 a warm place. Place another in the steam sterilizer for 

 five minutes. A third should remain 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 

 agnr-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, 



