38 
BULLETIN 1037, U. S. DEPARTMENT OF AGRICULTURE. 
0.66 per cent borax and boric acid, 0.20 per cent sulphur plus 0.20 
per cent lime, 0.10 per cent mercuric chlorid plus 0.20 per cent 
hydrochloric acid, 10 per cent potassium (alum), and 0.33 per cent 
phenol salicylate. He concludes that of these substances, 5 to 10 per 
cent sodium bicarbonate is the safest and best to use. 
In nearly all the cases cited the antiseptics proved to be of some 
value in preventing the growths of the sap-stain fungus. Molds, 
however, are extremely resistant to chemical treatment and con- 
sequently are difficult to control. To quote from Lafar (28) : 
" Whether the waterproof character of some cell membranes, e. g., 
the conidia of Penicillium and Aspergillus, should be attributed to 
Fig. 17. — Barrels and steam-coil connections as used in the experimental dipping of 
red-oak spokes at one of the large spoke mills in the South. 
the deposition of excreted fatty or waxy substances must be left 
undetermined. Biologically this phenomenon is important, since it 
prevents the penetration of toxic substances from the aqueous 
medium and thereby also opposes the attempts of the mycologist to 
kill such fungi by means of aqueous toxic solutions." Since, as has 
been stated repeatedly, molds develop largely on the surface of the 
timber and are sufficiently removed during the several finishing proc- 
esses to which the timber is sooner or later subjected, their presence 
in most cases should occasion but little concern in connection with 
vehicle stock. 
EXPERIMENTAL DIPPING OF RED-OAK SPOKES. 
In July, 1918, several series of experiments were performed by 
the writer in cooperation with one of the large spoke mills of the 
