May 16, 1921 
Respiration of Sweet Potato Storage-Rot Fungi 
217 
other words, 5. bataticola made nearly four times as much dry weight in 
nine days less time by the utilization of practically the same amount of 
sugar as F. acuminatum. Penicillium sp., on the other hand, utilized 
all the glucose and formed 6.25 gm. of mycelium, while Mucor racemosus 
consumed 25.8 gm. of sugar in making 1.13 gm. of dry weight. A study 
of the figures shows that there is no uniformity among the fungi as regards 
the glucose utilized and dry weight produced, even if an account is 
taken of the length of time they were grown. 
C 0 2 PRODUCTION 
In column 6 is shown the total amount of C 0 2 produced by each 
fungus during the time of the experiment. A comparison of the total 
C 0 2 given off with the dry weight produced and sugar utilized will not 
be necessary in all cases, but attention will be called to a few outstanding 
examples. Sclerotium bataticola gave off nearly twice as much C 0 2 as 
Fusarium acuminatum and yielded nearly four times as much dry weight, 
while Boirytis cinerea and Rhizopus tritici produced 32.71 and 2.72 gm. 
of C 0 2 , respectively, and formed 5.38 and 0.94 gm. of dry weight. Here 
also a resume of the figures shows that there is little or no uniformity in 
the relation of C 0 2 evolved to the glucose consumed and dry weight 
produced. 
RELATION OP C 0 2 GIVEN OFF TO GLUCOSE REDUCED 
The amount of C0 2 given off in grams for every gram of sugar reduced 
is shown in column 7. It will be seen that for Sclerotium bataticola , 
Penicillium sp., and Botrytis cinerea more than 1 gm. of C 0 2 is produced 
for each gram of sugar consumed. In all the other cases it is less than 
unity. It should be noted that these are the three fungi which produced 
the largest amount of dry weight and are among those which consumed 
the most glucose. If extremes are contrasted it will be seen that B . 
cinerea and Mucor racemosus produce approximately 1.2 and 0.5 gm. 
of C 0 2 , respectively, for each gram of sugar utilized. While some reasons 
for these differences will be suggested later, attention should be called to 
the fact that B. cinerea continued to give off an appreciable amount of 
C 0 2 some days longer than M. racemosus. Botrytis, Penicillium, and 
Sclerotium consumed all or practically all the sugar, so that it is not 
unlikely that other compounds were formed from the sugar which may 
have been utilized as a source of carbon. 
RELATION OF DRY WEIGHT TO GLUCOSE CONSUMED 
An examination of column 8 shows that the fungi differed greatly in 
the dry weight formed from 1 gm. of sugar consumed. Fusarium acumi¬ 
natum and Mucor racemosus stand out as conspicuous examples of fungi 
which produce a small amount of mycelium per gram of sugar used, this 
