38 



BULLETIN" 1037, U. S, DEPARTMENT OF AGRICULTUEE, 



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 antisejptics 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. 



EXPEEIMENTAL 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 



