146 BOTANICAL GAZETTE [AUGUST 
whereas boards dried in damp conditions in the open stain very deeply 
and densely. Boards treated in hot water and dried under cover 
remain unchanged in color throughout, and those placed in the most 
unfavorable conditions of abundant moisture and high temperature 
in the open, although they scorch superficially, as does all lumber 
exposed to the direct rays of the sun, remain unstained beneath this 
thin layer of tan. 
Practicability of hot water treatment 
It will occur to some readers that the activity of oxidizing enzymes 
could be prevented by kiln drying or steaming the wood, and that one 
of these methods would be more practicable than immersion in boiling 
water. However, to those familiar with saw mill practice it is evident 
that in mills sawing many thousand board feet of lumber each 
day and night it is usually difficult to steam or kiln dry more than 4 
small percentage of the cut. Steaming or kiln drying are expensive 
processes, and the latter can only be applied to certain varieties and 
grades of wood. Furthermore, these processes are time consuming 
and require much handling of the lumber. Some method must be 
devised for preventing sap stain which can be carried out very cheaply 
and rapidly, in order not to interfere with the movement of the lumber 
from the saw to the yard. In other words, the lumber must be 
removed, treated, and piled as rapidly as it is sawed, in order not ' 
interfere with the daily output of the mill. Some of the larger mills 
in the south have installed tanks containing chemical substances 
which destroy the action of oxidases and prevent discoloration by 
fungi. The lumber as it comes from the saw is carried through this 
tank upon carrier chains and thus immersed and coated with t 
chemicals. Certain difficulties have been encountered in the us 
of this method. One of the most serious is the fact that the chemicals 
used fire proof the outer surface of the boards, and when the treated a: 
lumber is shipped to northern markets for finishing the planings and 
shavings cannot be burned. This obliges the use of coal to run the | 
planers and other machinery, and the non-combustible planings must | 
be disposed of. 2 
In the treatment of lumber with boiling water a similar method 
could be employed. Long shallow tanks in which water 1s heated -— 
