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,” 
