DEVELOPMENT OF THE BACTERIA. 121 



bacteria, if Crova had not recently asserted that 

 movements impressed upon a liquid containing 

 bacteria completely arrests their development. 

 This is an assertion in complete opposition to all 

 that we know of the physiology of these organ- 

 isms, and which it is difficult to reconcile with the 

 fact that bacteria may develop even in the torrent 

 of the circulation. 



Compressed Air. We have just seen the in- 

 fluence of air, and especially of oxygen, upon the 

 bacteria. When this agent is in a certain state of 

 tension, it acts in a different manner. M. Paul 

 Bert has proved that under a tension of twenty- 

 three to twenty-four atmospheres all the putrefac- 

 tive processes depending upon the development of 

 vibrios cease to occur. Since, the same savant 

 has found that the anatomical elements and even 

 the red blood globules are killed by oxygen. 

 These researches agree well enough with those of 

 Grossmann and Mayerhauser upon the life of 

 bacteria in gas. From their numerous experi- 

 ments it appears that, under the influence of oxy- 

 gen, there is an exaggeration of the activity of 

 the bacteria; but if the oxygen is under a pres- 

 sure of five to seven atmospheres, the bacteria live 

 from six to twenty hours, then die, and cannot be 

 resuscitated by atmospheric air. 



Ozone causes a definite and almost instantaneous 

 arrest of movement. 



