240 BACTERIOLOGY. 



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. Con- 

 tinue 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 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 gel- 

 atin 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, 



