SAP-STAIN, MOLD, AND DECAY IN GREEN WOOD. 
47 
EXPERIMENTAL DIPPING OF BED-OAK BLOCKS AT THE LABOEATORY OF FOREST 
PATHOLOGY, MADISON, WIS. 
A comparison of the specific antiseptic values of the chemical sub- 
stances employed in the spoke-dipping experiments can hardly be 
made, since these substances were not used in solutions of uniform 
strength. To determine, if possible, the comparative values of these 
and several other common antiseptics and preservatives in the control 
of mold and sap -stain 
fungi, several series 
of experiments were 
undertaken at the 
Madison laboratory. 
Where possible, solu- 
tions were made up 
to a calculated value 
of 1 per cent actual 
weight of anhydrous 
salt. The hygroscopic 
substances — sodium 
chlorid, calcium 
chlorid, and glyc- 
erin — were added in 
certain instances to 
determine whether or not they would increase the efficiency of the 
preservative by keeping the surface of the treated wood moist. A 
list of the substances used follows : 
Fig. 21. — Storage of spokes in a warehouse. The truck 
spokes at the left have just been painted by girls with 
a resin-linseed oil mixture to prevent checking. 
Alum (potassium). 
Ammonium fluorid. 
Bleaching powder. 
Borax. 
Copper sulphate. 
Lead acetate. 
Lead nitrate. 
Magnesium silicofluorid. 
Mercuric chlorid. 
Mercuric chlorid and hydro- 
chloric acid, 1 per cent. 
Potassium chlorate. 
Sodium fluorid. 
Sodium bifluorid. 
Zinc silicofluorid. 
Creosote in kerosene. 
Formalin. 
Lysol. 
Mykantin. 
Orthonitrophenol. 
Rongalite. 
Red-oak blocks f by § by 1J inches long, sawed from the sapwood 
of summer-cut logs, were used in each case. Ten blocks constituted 
a group. The individual blocks of a group were immersed for ap- 
proximately 10 seconds in one of the respective solutions, drained, 
and then sprayed on all six sides with a water suspension of the 
spores taken from the same cultures as those used in the steaming 
experiments. 24 The sprayed blocks of each group were then close 
piled and placed in the tile chamber mentioned on page 29. An in- 
24 See page 29 for the list of fungi. 
