INFLUENCE OF VACUTJM UPON GROWTH OF BACTERIA 287 



1 oc. of a suspension of spores added. The spores were sus- 

 pended in salt solutions to correspond to that in the tube, so that 

 the salt concentration was not changed. All the tubes were 

 filled to a mark on the constriction, with broth containing cor- 

 responding amounts of salt. A certain per cent of this was then 

 removed and the tubes exhausted and sealed at the mark. The 

 tubes were then incubated at 37°C. for twenty-seven days and 

 plates made. 



TABLE 1 



Since each tube had a slightly different amount of broth added, 

 it was necessary to calculate how many organisms were present 

 in each centimeter of liquid in the beginning. These numbers 

 are in one column and the number at the end of the incubation 

 period in a parallel column. The volume of air varied from 0.3 

 cc, in the tubes containing 1 per cent air to 1.5 cc. in the tubes 

 containing 25 per cent air, each tube being of somewhat different 

 volume from the others. The results are shown in tables 2 and 3. 



These tables show the same as table 1, that there is some 

 growth in these tubes. There is an interesting point relative to 

 the action of increased amounts of salt. In every case, when 

 the average is taken for all tubes in the same concentration of 

 salt, there is an increase over that of a lower concentration. 

 This point is somewhat more in evidence in connection with 



