RELATION TO OXYGEN. 53 
should be disturbed as little as possible after inoculation, and especially all tiltings 
or rough jarring should be avoided. They may be carried in a wooden rack (fig. 46). 
All culture-media, whether inoculated or not, should be protected from light. 
Figs. 47, 48, 49 show fermentation-tubes in actual use. 
The pattern of fermentation-tube preferred by the writer is that slight modi- 
fication of Einhorn’s tube designed by Dr. Theobald Smith (see Wilder Quarter 
Century Book). ‘The tubes may be had from Emil Greiner, New York. Certain 
Hrs. 
26 
50 
78 
Fig. 47.* Fig. 48.7 Fig. 49.4 
forms of tubes should not be used. One of these, a short, thick tube with a wide 
U, in use in some laboratories in this country, allows air to pass readily into the 
closed end and is entirely worthless. A sample tube of this sort was filled with 
*Fic, 47——Fermentation-tube with Bacillus tracheiphilus, showing absence of gas and uniform 
clouding in open and closed end in the presence of grape-sugar. The fluid consisted of water, 400; 
Savory & Moore’s peptone, 4; sodium chloride, 1; c. p. grape-sugar, 2; saturated solution carbonate 
of soda (20° C.), 20 drops, i. e., enough to render the fluid slightly alkaline to litmus. 
tFic 48.—Fermentation-tube with Bacillus tracheiphilus, showing inability of organism to grow 
anaerobically with glycerin as the carbon food. Fluid, distilled water with 1 per cent Witte’s pep- 
tonum siccum and 1 per cent Schering’s c. p. glycerin. Copious growth in open end and in outer 
part of U; none in the closed end, 
tFic. 49—Fermentation-tube of cane-sugar peptone water inoculated with a white, gas-forming 
organism plated from a spot disease of sisal hemp. The total amount of gas produced and its rate 
of evolution at 20° to 23° C, are indicated by marks on the closed end of the tube. 
