Bulgaria polymorpha , WetL 1 2 7 
Tamus communis. Gardiner 1 has shown in these that the 
cytohydrolytic enzymes travel along the protoplasmic threads 
traversing the walls and dissolve them in their immediate 
neighbourhood. The action is most intense near the middle 
lamella, so that each thread seems to lie in a cone-shaped 
portion of the partially dissolved wall, the base of the cone 
resting on the middle lamella. Sections in the plane of the 
threads would therefore show a more or less lens-shaped patch 
of partially dissolved cellulose. 
Although, as far as I know, no one has yet proved that 
threads exist in woody walls similar to those we are dealing 
with, yet it seems probable that they existed while the 
thickening layers were being deposited, so that there is 
a possibility that the pits and the walls are traversed by 
the minute passages they once occupied. If this is in reality 
the case, we may apply Gardiner’s explanation of the destruc- 
tion of the cellulose endosperm-walls to the destruction of the 
lignified walls, by assuming that a delignifying enzyme travels 
along the slender passages formerly occupied by the threads 
and decomposes the lignin in their neighbourhood. Whether 
the increased intensity of decomposition near the middle 
lamella is due to slight differences in the structure of the 
succeeding strata of the cell-walls or not has still to be proved. 
At all events, the first appearance of these delignified lens- 
shaped patches and the gradual and regular spread of the 
delignification from the pits accord so well with the assump- 
tion made as almost to amount to a proof of the existence 
of protoplasmic threads, or of the passages once occupied by 
them in woody walls. 
So far I have assumed the existence of a delignifying 
enzyme to explain these results. Such an enzyme has 
recently been isolated by Czapek 2 from Merulius lacrymans 
and has been named Hadromase. Before seeing Czapek’s 
paper I had considered that there was evidence for lignin 
being a glucoside capable of being split into pectic acid and 
1 Gardiner, Proc. Roy. Soc., 1897-98, vol. Ixii, p. 100. 
2 Czapek, Ber. d. deutsch. bot. Ges., 1899, xvii, p. 166. 
