REPRODUCTION BY SPORES. 35 
(4) Add to the bouillon a very small portion of 
a culture of Bactllus subtilis, or any chain-forming 
and spore-producing species. 
(c) Mount as a hanging-drop preparation and 
place in the incubator. 
(d7) Examine at intervals of one-half hour. 
Notice the elongation of the bacilli and the for- 
mation of chains. 
(e) Inoculate a bouillon-tube as directed on page 
60. 
(/) Place in the incubator and make stained 
preparations at half-hour intervals. “ 
Preserve both hanging-drop preparation and 
bouillon-tube for further examination. 
II. Reproduction by Spores. 
1. After the formation of chains has taken place 
in the above cultures, continue the examination at 
intervals. The formation of spores within the rods 
will be observed ; finally, the rods will disappear 
and nothing but spores remain. 
a 4 é ad e ft 
ce> <2 ' oe eS @€ 
-Fic. 17.—Diagram illustrating sporulation: a, bacillus 
enclosing a small oval spore; 6, drumstick bacillus, with 
the spore at the end ; ¢, clostridium ; d, free spores ; é, and 
J, bacilli escaping from spores. 
2. Make stained preparations from the bouillon 
culture when rods and spores within the rods and 
spores alone are all present. Stain as follows: 
