DEVELOPMENT OF THE BACTERIA. 117 



bacteria will all approach gradually to the margins 

 of the cover ; and it is there that at the end of 

 several days, after the successive death of the 

 greater number, some are still found endowed with 

 life and movement. If a similar preparation is at 

 the same time protected by an impermeable ce- 

 ment against dessication and against the introduc- 

 tion of atmospheric air, all movement among the 

 bacteria will cease at the end of two minutes, pro- 

 vided, however, that no air bubble has been im- 

 prisoned with the liquid." 



The influence of oxygen upon the life and de- 

 velopment of bacteria is also very manifest in an 

 experiment recently made, and not yet published, 

 by Toussaint, who has been kind enough to com- 

 municate it to me. 



In studying the development of the spores 

 of Bacillus anthracis in the moist chamber of 

 Ranvier, Toussaint has observed the following 

 curious facts, which offer a striking analogy to 

 those above mentioned, borrowed from Hoff- 

 mann. " The bacteria, which occupy the cen- 

 tral portion of the moist chamber and which 

 by reason of their situation receive very little 

 oxygen from the groove, are soon arrested in 

 their development ; while those which occupy the 

 borders are long and heaped up in immense num- 

 bers, those in the centre remain small, formed of 

 two, four, or five articles, which are easily sepa- 

 rated from each other; they soon cease to grow 

 and are not transformed into spores." 



Cohn is also as explicit. " There is no doubt," 



