8o 



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 

 stopper may be use to prevent 

 drying, see page 86. 



Fig. 21. — Smear culture. This 

 tube shows the rubber cap used to 

 prevent dr3ang. 



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- 

 *Zeitschrijt. j. Hygiene Bd. 25, 1897, p. 179. 



