6 BULLETIN 1262, U. S. DEPARTMENT OF AGRICULTURE. 
infected wood are then cut and pried out of the block with this instrument 
and placed in sterile test tubes containing plain malt agar. The area from 
which each fragment iS removed is numbered and the test tube containing 
it is similarly marked. The block when removed from the clamp shows the 
numbered hollows (Pl. III, C) and their distribution over the face of the 
block. A sketch was made of the split block, showing the areas from which 
fragments were removed, indicating the stages of decay and the limits of the 
discolored areas. 
A large percentage of the cultures are contamination free, and an average 
of 96 to 100 tube cultures can be made in two hours. When three out of six 
tubes showed contamination, or when results seemed doubtful, the cultures 
were repeated. 
Plain malt. agar° was used in the tubes and the surface of the agar slanted. 
All. cultures were grown at room temperatures and were kept for a minimum 
period of six weeks, in order to observe the negative cultures and watch for 
delayed revival of the fungi in the inoculum. A negative culture is shown in 
Plate V, A, and a positive culture in Plate V, B. 
KILN-DRYING AND STEAMING EXPERIMENTS. 
RUN 1. 
A set of test pieces of the Neopit and Oakridge material was placed 
in a small experimental dry kiln for a period of 16 days. : 
The temperature range during the run was from 120° to 135° F. 
The relative humidity averaged 85 per cent during the test, with a 
range between 100 and 70 per cent. 
Cultures made from the blocks removed from the test pieces at the 
end of the run showed all the fungi to be dead within the centers 
of all the 1-inch, 2-inch, and 4-inch pieces. 
RUN 2. 
Eighteen spruce (Picea canadensis) pulp logs received from 
northern Wisconsin were sawed into test planks 2 by 10 by 48 inches. 
These logs were infected in the storage pile by various wood-destroy- 
ing fungi, and in most cases both the typical stage and the incipient 
stage of decay were included in the test planks. Im many cases the 
rots of more than one fungus were present in the same test plank. 
A set of 20 planks was placed in a Tiemann dry kiln along with a 
commercial run of 24-inch bald cypress lumber for a period of 40 
days. Three planks of western yellow pine (Pinus pondcrosa) in- 
fected with Polyporus anceps and 15 pieces from the Neopit material 
were also added. The initial temperature was 95° and the end tem- 
perature 160° F. During the kiln drying the relative humidity 
ranged between 50 and 84 per cent. At the end of the run, culture 
blocks were cut from the center of each plank. Cultures were made 
in the usual manner, and it was found that all the fungi had been 
killed. 
RUN 3. 
A set of test pieces of the Neopit and Oakridge material combined 
was placed in a Tiemann dry kiln for a period of 12 days. The set 
was placed on top of a charge of oak lumber. 
The temperature range during the run was from 143° to 168° F. 
The relative humidity averaged 57 per cent during the run, with a 
range between 28 and 95 per cent. 
5 Distilled water, 1,000 cubie centimeters; Trommer malt extract, 25 grams; agar (pow- 
dered), 15 grams, 
y 
