24 ColJer/e of ForeMry 



these i)roducts results in tlie formation of the brown drops 

 which hiter become solidified and occlude the vessels. More- 

 over, in coniferous woods which are killed by fungi the brown 

 drops occurring in the parenchyma cells are, to all appear- 

 ances, of' the same nature and manner of origin. 



With regard to the transformation of the cell contents of 

 coniferous woods, Miinch cites an experiment by which he 

 could follow, microscopically, the entrance of a bluing 

 fungus, Endoconidio'pliora coeridescens, into the parenchyma' 

 cells of pine wood. He made thin radial sections from living 

 pine wood and ]3laced them in hanging drops in van Tieghem 

 cells, the whole being done under sterile conditions. In the 

 case cited the reserve material consisted entirely of fat in 

 the form of a fine emulsion in the protoplasm. If no infec- 

 tion followed he noted that such cells in a hanging drop cul- 

 ture remained unchanged for several day's. If, on the con- 

 trary, viable fungous spores were inoculated into the drop 

 culture he observed that the conditions changed at once. As 

 soon as the fungal hyphae reached a pith ray they promptly 

 invaded it, ramified, and soon filled the cells completely. He 

 observed that the fine granular structure of the protoplasm 

 immediately disappeared into the cells attacked and the con- 

 tents flowed together into drops. Upon careful observation, 

 minute thin-walled fungal hyphae were always to be found 

 in the cells thus altered. These drops were still colorless at 

 the end of the experiment and were (as Miinch learned by 

 comparison of other tests of wood killed by such fungi) 

 similar in every way to those previously described by Frank 

 except that they did not become l^rown. That this substance 

 can also occur in the parenchyma cells of coniferous wood had 

 been found previously by Will (1899). 



The writer has never observed nor could any reference in 

 literature be fonnd concerning the occurrence in coniferous 

 woods attacked by wood-destroying fungi, of the prominent 

 blackish zones which are characteristic features associated 



