26 BULLETIN 606, U. S, DEPARTMENT OE AGRICULTURE. 
Maple, sugar (Acer saecharum) — heart wood. —Sugar maple is a 
diffuse-porous wood. In the specimens tested tyloses were not pres- 
ent in either sapwood or heartwood, but gums and infiltrating sub- 
stances were present. The specimens showed a more or less variable 
penetration. In the cylinder treatments some of the pieces were well 
penetrated and others were penetrated but a short distance or in 
streaks. Creosote penetrated chiefly in the wood prosenchyma, 
although it was also present to some extent in the vessels. The pres- 
ence of gums seems to be responsible for the variable penetrations 
secured in the tests. 
Oak, our (Quercus macrocarpa). — Tyloses are numerous in both 
sapwood and heartwood of bur oak. The effect of tyloses on pene- 
tration is very marked in this species, and it was found to be almost 
impossible to penetrate the heartwood to an appreciable extent. 
Yery little creosote was found in the vessels, which seemed to be 
effectively blocked by tyloses. Two or three of the specimens treated 
in the cylinder showed a fairly good penetration in part of the wood. 
The distinct demarcation of the treated and untreated areas seemed 
to indicate that the wood which was penetrated might have been sap- 
wood not clearly distinguishable before treatment. The medullary 
rays were practically untreated in all of the tests. 
Oak, chestnut (Quercus prinus) — heart wood.^-The structure of 
chestnut oak is very similar to that of red oak, being ring-porous and 
generally without tyloses, although botanically chestnut oak is 
classed as a white oak. Penetrance tests could not be made on this 
species on account of the open condition of the vessels. Penetration 
took place mainly in the vessels or pores. The cell walls were prac- 
tically impenetrated by the preservative. Railroads have frequently 
classed this species with the white oaks and installed chestnut oak 
ties in the track without treatment. Since the wood takes treatment 
easily and the pores generally are without tyloses, chestnut oak ties 
should evidently be treated with a preservative. 
Oak, red (Quercus rubra) — heartwood. — There are practically* no 
tyloses in the vessels of red oak. On account of the very porous con- 
dition of the wood, penetrance tests could not be made. Specimens 
treated in the cylinder were penetrated largely in the vessels, but very 
little in the heartwood prosenchyma. The sapwood prosenchyma, 
however, is known to take treatment very easily. 
Oak, white (Quercus alba) — heartwood. — The pores in both sap- 
wood and heartwood of white oak are filled with tyloses. These 
tyloses and the character of the wood prosenchyma were an important 
factor in making it difficult to secure more than a very slight pene- 
tration in the specimens tested. Yery little creosote was found in 
either the vessels or wood prosenchyma. The tyloses were found to 
be unpenetratecl even in those portions of the wood which had been 
treated. 
