222 
Journal of Agricultural Research 
Vol. XXI, No. 4 
In no case was enough C 0 2 produced to account for all the glucose 
used up, so that the question of what became of the remainder of the 
glucose naturally suggested itself. Attention already has been called 
to the fact that many fungi produce alcohol in nutrient solutions. Ac¬ 
cording to Jost (jj) a io per cent solution of alcohol is usually injurious 
to fungi, while a 2 to 4 per cent is usually nutritive. Sclerotium batati- 
cola , Penicillium sp., and Boirytis cinerea did not produce alcohol accord¬ 
ing to the iodoform test, and yet they used up all or nearly all the glucose. 
While the writers have no proof to offer, it is possible that alcohol was 
formed by these organisms which was utilized by the fungi as a source 
of carbon. 
Positive iodoform tests were obtained for Rhizopus tritici , Diplodia 
tubericola f Fusarium acuminatum , and Mucor racemosus , while Boirytis 
cinerea } Sclerotium bataticola, and Penicillium sp. gave negative results. 
It will be seen that the last three organisms produced more than 1 gm. 
of C0 2 for each gram of glucose used, while the first group gave off con¬ 
siderably less. The distillate from the solution on which M. racemosus 
grew gave an especially heavy precipitate of iodoform crystals. 
Under the conditions of the experiment Rhizopus tritici and Diplodia 
tubericola produced only a trace of alcohol. A separate experiment was 
conducted to test further the ability of the former organism to form 
alcohol. Flasks were prepared in triplicate, with the same medium as in 
the previous experiments and 10 per cent glucose as the source of carbon. 
All three of the flasks were inoculated, two being stoppered with rubber 
corks and one with a cotton plug. A normal growth of mycelium took 
place in the flask stoppered with cotton, but in the other two flasks the 
mycelium was abnormal in appearance, less luxuriant, and mostly sub¬ 
merged. Distillations were made from all the solutions, and as indi¬ 
cated by the iodoform test an abundance of alcohol was formed in the 
flasks stoppered with corks, while only a mere trace could be detected 
in the flask plugged with cotton. It would seem then that R . tritici 
will produce alcohol much more readily when growing on the medium 
used in the experiments recorded above when a reduced supply of oxygen 
is available and intermolecular respiration is thereby induced. The 
concentration of the C 0 2 would be increased also under these conditions. 
In the respiration experiment, as indicated by the amount of C 0 2 pro¬ 
duced per gram of sugar used, it is possible that considerable alcohol 
was formed and possibly a part of it was carried off by the air current 
continually passing through the flask. However, some of the sugar may 
have gone to form other organic substances. 
Organic acids. —The nutrient solution with which these experiments 
were conducted was slightly acid at the beginning. In a paper by Wei- 
mer and Harter (23) it was shown that all of these same organisms when 
growing in a 10 per cent glucose solution increase the P H value of the 
solution and some of them to a considerable extent. It has been hither- 
