Preservative Treahnent of Wood. lo 



5. When wood is thoroughly dried no structural modification, 

 such as the rupturing of the cell walls, is essential in order to 

 account for the penetration of gases and preservatives into 

 seasoned wood. 



6. In green wood the bordered pits and membranes are very 

 permeable to aqueous solutions, but are comparatively impervious 

 to undissolved gases, and to oils, and other heavy or viscous 

 liquids. This is due undoubtedly to capillary or surface tension 

 phenomena and the valve-like action of the torus. 



7. Dry wood (except when the cells are clogged with resins or 

 other secretions) is very permeable to gases, since water is no 

 longer present to resist the passage of the gases through the 

 perforations in the pit membranes. 



8. Whenever preservatives are injected rapidly into green or 

 seasoned wood the penetration takes place primarily through the 

 cavities of the cells, and the preservatives pass from one cell to 

 another through the bordered pits. 



9. Rupturing of the pit membranes was found in some speci- 

 mens to be a concomitant of the process of drying, and may ac- 

 count for the fact that in certain cases resoaked dry wood is 

 less impervious to aii than green material. 



10. The impregnation of wood by modern commercial methods 

 is a complicated chemical, physical, and anatomical problem, since 

 any given phenomenon may be the result of numerous, interacting 

 chemical, physical, and anatomical factors. 



Bibliography. 



1. Boucherie, A. Nouvelles recherches sur la conservation des bois. 



Compt. Rend. 12, 1841. 



2. Dippel, L. Das Mikroskop und seine Anwendung. Erste und Zweite 



Abtheilung. Friedrich Vieweg und Sohn, 18^ and 1898. 



3. Dixon. H. H. and Joly, J- The Path of the Transpiration Current. 



Annals of Botany, 9, 1895. 



4. Elfying, Fr. Ueber die Wasserleitung im Holz. Bot. Zeit., 1882. 



5. Errera, L. Ein Transpiration Versuch. Ber. d. Deutsch. Bot. Ge- 



sellsch. 1886. 



6. Gardiner, W. On the Continuity of Protoplasm through the Walls of 



Vegetable Cells. Arb. d. bot.' Inst. Wurzburg, Bd. Ill, 1884. 



7. Godlewski, E. Zur Theorie der Wasserbewegung in den Pflanzen. 



Pringsheim's Jahrb. f. Wiss. Bot. b. XV. h. 4, 1^4. 



8. Hartig, R. Holzuntersuchungen. Julius Springer, Berlin, 1901. 



9. Hortig, Tr. Ueber die Bewegung des Saftes in den Holzpflanzen. 



Bot. Zeit., 19. i86r. 

 10. Hohnel. Notizen iiber die Mittellamelle der Holzelemente und die 

 Hoftiipfelschliessmembran. Bot. Ztg., 1880. 



