1921] 
MATSUMOTO—SPECIALIZATION IN RHIZOCTONIA 17 
earlier than that of Bl and P4. Asa rule P7 produces no scle- 
rotia, so that its mycelium was taken at the time of the collection 
of material of B1 and P4. Growth of B3 was so slow and poor 
that sometimes enough material for the investigation was not 
obtained. 
CARBOHYDRATE METABOLISM WITH SPECIAL REFERENCE TO 
ULTURAL AND ENZYME STUDY 
Much of the literature dealing with carbohydrases of fungi 
is discussed in the work of Zeller (16) and will not be given here. 
From what has preceded it is apparent that no single temperature 
adapted for this work would be the optimum for all strains. 
Nevertheless, 25° C. is favorable for all. Therefore, in the 
present investigation, if no special mention concerning this 
factor is given, it will be understood that all the cultures are kept 
at 24-26? C. After a certain period of incubation the cultures 
were filtered and the mat of the mycelium washed several times 
with distilled water and finally dried in the oven after the method 
described by Duggar and his associates (17). Each weight was 
read twice at different times, and an average number was taken 
for the result. All experiments were made with cultures of the 
various strains of the same age grown on the same media. "The 
determination of the H-ion concentration, within the limit 
shown in the following culture media, does not seem to be a 
limiting factor for the growth of the various forms of Rhizoctonia. 
Therefore in this investigation H-ion concentration may be 
considered negligible. 
STARCH AND SUCROSE 
Cultural experiments.—Of each of the following carbohydrates, 
glucose, cane sugar, and soluble starch, 2 per cent solutions were 
prepared, and as solvent the well-known Richards' solution, 
containing as here modified, NH,NO,, 1 gm., KNO,, .50 gm., 
KH,PO, .25 gm., MgSO, .25 gm., peptone, 20 gms. and 
distilled water, 1000 cc. 
Twenty-five cc. quantities of each of the above-mentioned 
solutions were placed in 125-cc. Erlenmeyer flasks. Dupli- 
cates of all of these were inoculated with each strain, and the 
work was done in a culture room in which all dust was thoroughly 
