SAP-STAIN", MOLD, AND DECAY IN GREEN WOOD. 



33 



alkaline conditions. To this group belong sodium carbonate, sodium 

 bicarbonate, sodium hydroxid, lime, and borax. Others are intended 

 to poison the food of the fungi, and comprise such compounds and 

 mixtures as mercuric chlorid, copper sulphate, sodium fluorid, creo- 

 sote, and many other substances. 



Toxicity tests (Humphrey and Fleming, 2Jf.)^^ conducted at the 

 Madison laboratory upon a few molds commonly occurring upon 

 infected timber, as well as upon several wood- destroying fungi, have 

 clearly demonstrated that when the entire culture medium is perme- 

 ated with these and many other preservatives, often in very small 

 amounts, the growth of the fungus can be readily inhibited. Hence, 



Pig. 14. — Preparator used for the commercial steamiug of red-gum lumber at one of 



("he mills In Arkansas. 



if wood be thoroughly impregnated with a solution of one of these 

 common preservatives it will be protected from decay as well as from 

 sap-stain and mold. 



This is quite possible in the case of thoroughly seasoned timber 

 impregnated with preservatives by subjection to high pressure in 

 closed retorts. The penetration of green timber by cold solutions 

 of salts in an open tank or by the brush treatment, however, is ex- 

 tremely slight.^^ Tests made by the writer for the presence of cop- 

 per in the interior of f by f by 1^ inch blocks sawed from the green 



=0 Information also obtained from unpublished reports of toxicity experiments per- 

 formed by Miss C. Audrey Richards at the Laboratory of Forest Pathology, Madison, Wis. 



^ For a description of the pressure, open-tank, and brush treatments, the reader is re- 

 ferred to Forest Service Bulletin No. 78 (45) and to Farmers' Bulletin 744 (25), U. S. 

 Department of Agriculture. 



