SAMPLE BOTTLES 5 
of dilution water, it may be sterilized in larger quantities and delivered 
under aseptic conditions in any required amount to the sterile dilution 
flask. Frost has shown that during sterilization the volume in dilution 
bottles may be changed and this might cause considerable error where 
accuracy is desired. 
Sample Bottles. A glass-stoppered bottle of any type may be used. 
The necks should be wrapped with tin foil before sterilization. Great 
care should be taken to secure bottles which possess tight stoppers. 
In general a bottle with a narrow neck is preferable since the possibility 
of contamination during analysis is greatly decreased. 
Fie. 4.—Types of Flasks for Bacteriological Work. 
“A, Koch’s Culture Flask, B, Fernbach’s Antitoxin Flask, C, Freudenreich’s; D, Lister Culture 
Flask, E, Miquel Flask; ¥F, Kolle Culture for Growing Bacteria in Large Numbers, G, Roux 
Flask, H, Piorowshi’s Flask. 
Flasks. Many of the flasks which are used for bacterial work are no 
different from those used in chemistry. Other flasks have been in- 
vented for special purposes and usually bear the name of the originator. 
A few are given in Fig. 4. 
Slides and Cover Glasses. Slides should be made of clear white 
glass and should be free from defects. Different sizes are available but 
those which are 2.57.7 mm. have widest use. 
Cover glasses are classified as No. 1, No. 2, and No. 3. The follow- 
ing thicknesses are characteristic of each number. No. 1, zoo to 150 in. 
