YEASTS . 
43 
sixteenth of a cake of compressed yeast. Put each 
portion into a clear glass bottle or tumbler and place 
all three in a warm place, about 75 0 or 8o° F., for an 
hour or two. Watch carefully for the first sign of 
bubbles which show that gas is forming. Note in 
which glass the larger amount of gas is found. 
FIG. 26. YEAST GENERATING CARBON DIOXIDE. 
(a) Tube filled with molasseg and water. 
(b) Carbon dioxide collecting In top of tube. 
Fill a test tube or thin, clear glass vial with a 
mixture of molasses and tepid water. Add a little 
yeast and invert the vial in a dish which also con¬ 
tains molasses and water. Fasten the vial so that it 
will remain standing, closed, in the dish for a day or 
more. Fig. 26 j a and. b % 
