FILLING THE TUBES. 107 



each of three successive days. During the intervening 

 days they may be kept at the ordinary room tempera- 

 ture. 



When sterilization is complete, and the medium in 

 the tubes is still liquid, some of them may be placed in 

 a slanting position, at an angle of about ten degrees with 

 the surface on which they rest, and the medium allowed 

 to solidify in this position. These are for the so-called 

 slant cultures. The balance may solidify in the erect 

 position ; these serve for the plate cultures. 



For Esrnarch tubes not more than 5 c.c. of material 

 should be placed in each tube, as more than this renders 

 the rolling difficult and irregular. 



