So MANUAL OF BACTERIOLOGY. 



and is employed in case of material containing a small number 

 of bacteria. 



When a tube of gelatin is to be inoculated the wire is 

 usually introduced into the medium vertically, " stab-culture;" 

 when a medium with a slanted surface is employed, as agar, 



FIG. 20. Stab culture. A rubber FIG. 21. Smear culture. This 



stopper may be use to prevent tube shows the rubber cap used to 

 drying, see page 86. prevent drying. 



potato or blood-serum, the needle should lightly streak the 

 surface, " smear culture" (Figs. 20 and 21). 



The safety and success of this method of inoculation depend 

 upon a principle which has been established by long and re- 

 peated observation, namely, that bacteria do not of them- 

 selves leave a moist surface, although they may be readily 

 shaken off as would appear from Flugge's* results. Neverthe- 



*Zeitschri/t. /. Hygiene Bd. 25, 1897, p. 179. 



