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1910] BAILEY—SAP STAIN IN LUMBER 145 
ture produce similar variations in the activity of the discoloring 
agency. — 
Prevention of Sap stain 
The fact that the temperature of boiling water destroys the activity 
of oxidases and peroxidases suggested to the writer the idea, that if 
sap stain were produced through the action of oxidizing enzymes, a 
simple method of preventing the discoloration of sap wood might 
be secured by immersing lumber in boiling water. During the spring 
of the present year the writer has tested this method on small boards 
(1X 3’’X6") of Alnus incana Moench., Betula populifolia Marsh.., 
B. papyrijera Marsh., and various rosaceous trees. These species 
were selected as, at this latitude (Massachusetts), the sap wood stains 
very easily and rapidly during the spring upon exposure to the air, 
whereas the sap wood of such trees as sweet gum, maple, and basswood 
stain deeply during extremely hot and humid summer weather. The 
result of these tests has been to show that boards immersed in boiling 
water for a few minutes remain permanently unchanged in color, 
Whereas untreated pieces stain rapidly and deeply. The fact that 
the unboiled boards stained on exposure to the air and that the dis- 
coloration was prevented by boiling offered strong evidence for believ- 
ing that sap stain results from the action of oxidizing ferments. On 
testing boiled and unboiled boards with the guaiacum tests, the blue 
color produced in the unboiled boards demonstrated the presence 
of oxidizing enzymes. 
In conducting these experiments the boards which were to be 
boiled and those which were to serve as controls were in all cases cut 
from the same part of the same tree, and were subsequently exposed 
to the same atmospheric conditions of temperature and humidity. 
The extreme sensitiveness of oxidizing enzymes in their oxidizing 
activity was clearly demonstrated by the species of wood used in 
these tests. For example, alder and birch, which in hot, humid 
weather stain in a few minutes to a reddish yellow or rusty color, 
stain more slowly at lower temperatures, and in cold dry weather 
stain but slightly even after an interval of several weeks. In a similar 
way the depth to which the stain penetrates into the wood varies with 
temperature and moisture. Boards dried in sheds stain superficially, 
