KOLLE'S CULTURE FLASKS 5 



on account of the large nutrient surface available for 

 growth. A surface cultivation in one of these will 

 yield as much growth as ten or twelve "oblique" tube 

 cultures. The wide mouth, however, is a disadvantage, 



FIG. 4. Kolle's cul- 

 ture flask. 



FIG. 5. Roux's 

 culture bottle. 



FIG. 6. Guy's culture 

 bottle. 



and for many purposes thin, flat culture bottles known 

 as Roux's bottles (Fig. 5) are to be preferred. 



An even more convenient pattern is that used in the 

 author's laboratory (Fig. 6), as owing to the greater 



FIG. 7. Filter flask. 



depth of medium which it is possible to obtain in these 

 flasks an exceedingly luxuriant growth is possible; the 

 narrow neck reduces the chance of accidental contami- 

 nation to a minimum and the general shape permits 

 the flasks to be stacked one upon the other. 



