238 FOUNDATIONS OF BOTANY 



organisms in a flame, and lay each on a saucer, with cut surface up, 

 covering each with a glass tumbler. The tumblers and saucers 

 should be well scalded or kept in boiling water for half an hour and 

 used without wiping. Sterilization may be improved by baking 

 them in an oven for an hour. 



265. Inoculation. — The culture media prepared as above may 

 now be inoculated. Uncover them only when necessary and quickly 

 replace the cover. Scrape a little material from the teeth, tongue, 

 kitchen sink, floor of house or schoolroom, or any other place you 

 may desire to investigate. With the point of a knife blade or a 

 needle sterilized in a flame, inoculate a particle of the material to be 

 cultivated into the surface of one of the potatoes. Several cultures 



T^"^ 



\ 



BCD E 



riG. 174. — Bacteria stained to show Cilia. 



A , Bacillua subtilis ; B, Bacillus typhi (the bacillus of typhoid fever) ; C, Bacillus 

 tetani (the bacillus which causes lockjaw) ; 2), Spirillum undula; S, Bacillus 

 teiami forming spores. (All five are magnified 1000 diameters.) 



may be made in this way and one or more left uninoculated as 

 checks. Another may be left uncovered in the air for half an hour. 

 Others may be made with uncovered potatoes. Number each culture 

 and keep a numbered record. 



Keep watch of the cultures, looking at them daily or oftener. As 

 soon as any change is noticed on the surface of a culture, make a 

 descriptive note of it and continue to record the changes which are 

 seen. Note the color of the areas of growth, their size, outline, ele- 

 vation above the surface, and any indications of wateriness. Any 

 growth showing peculiar colors or other characters of special inter- 

 est may be inoculated into freshly prepared culture media, using 

 any additional precautions that are practicable to guard against 

 Qontaminatjon. 



