The writer wishes to, discribe the decomposition or the utilization of cellulose by wood-destroying fungi relating to the macroscopic appearances of rotted wood attacked by the fungi and to BAVENDAMM'S “Oydationszonen” on gallic acid medium caused by them.
(1) The wood-destroying fungi studied in the present investigation and the macroscopic features of decayed wood attacked by these fungi are as follows:
Fomes pinicola (SCHWARTZ) FR.…brown cubical rot,
Poria. vaporaria PERS.………… cubical rot,
Lenzites styracina HENN. ET SHIRAI…pale-brown rot_??_white rot,
Polyporus japonicus FR.…white spongy rot,
Trametes pini (TxoRE) FR.…white pocket rot,
Ganoderma applanetum (WAULR) PAT.…white rot,
Polystictus sanguineus (L.) FR.…brown spongy rot,
Cortinellus Berkeleyanus S. ITO ET IMAI…pale-brown rot_??_yellow rot,
Polyporus Mikadoi LLOYD…pale-brown rot_??_white pocket rot,
Potyporus rhodophaeus REV…white rot.
All these fungi are found most commonly in Japan.
(2) The fungi listed above with the exceptions of Fomes pinicola and Poria vaporaria formed so-called BAVENDAMM'S “Oxydationszonen” on the media containing low concentration of gallic acid.
(3) In testing the ability of these wood-destroying fungi to utilize cellulose as a source of nutrition, the fungi were grown on the media containing colloidal cellulose as the only organic nutritional material. This colloidal cellulose was prepared from filter paper by use of the sulphuric acid method and of SCHWEITZER'S reagent. The compositions of the plate culture media used in the experiments are following:
Medium No.0=M₀: Distilled water, 1, 000 cc., agar-agar, 30g.,
Medium No.1=M_I: Colloidal cellulose prepared by use of sulphuric acid method, 1, 000c.c., agar-agar, 30g.,
Medium No.2=M_II: Colloidal cellulose prepared by use of SCHWEITZER'S reagent, 1, 000cc, Mg SO₄, 0.5g., K₂HPO₄, 1g., KCl, 0.5 g., FeSO₄, 0.1 g., agar-agar, 30g.
(4) In the experiments, the mycelial growth of the fungi, especially Poria vaporaria, Polystietus sanguineus and Cortinellus Berkeleyanus, on the culture medium No.1 was abviously more vigorous than that on the medium No.o.
(5) When the fungi had been grown for 5 days on the plate culture medium No.2 at 25-C, iodine-solution was poured on the surface of the plates, and in a little while, no-colored or semitransparent portions were appeared around the developed colonies of the fungi, proving that cellulose in the medium near the mycelial colony has been utilized by the fungi.
Taking the results of the expiriments, it may be said that all fungi studied in this investigation are, more or less, able to decompose cellulose. In order to compare with the degree of cellulose-dissolving abilities of these fungi, the writer has made an attempt to use the following formula,
where, φ: the degree of cellulose-decomposing ability of the fungus, α: the diameter of the fungal colony on the Medium No.2,
β: the diameter of the no-colored portion on the medium by iodine-solution,
but in vain gained the indubitable conclusion correlating with the macroscopic appearances of rotted wood and BAVENDAMM'S reactions. The degrees of the cellulose dissolving abilities in wood-destroying fungi given by this formula are shown in the following table:
(15) The facts above mentioned indicat that, on the chemical standpoint of view, the phenomena of wood-decaying, containing lignin-and cellulose-resolution, are too complex to be explained by the results of such simple experiments.

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