Fischer , — The Biology of A r miliaria mucida , Schrader . 529 
II. Action of the Fungus on the Tissues. 
Methods.— In order to investigate the action of the hyphae on the 
wood of its host the following methods were employed. 
Diseased wood brought in from Windsor Park was sawn into convenient 
sections and fixed in one of the following solutions : — 
Merkels solution. 
Flemmings weak solution. 
Absolute alcohol. 
Picric acid. 
Sections were cut freehand and tested with iodine, chlor-zinc-iodine, 
phloroglucin, alkalin, &c., and were stained by the methods detailed below. 
At all stages sections of sound wood were treated in the same manner 
for comparison. 
The stains employed were : — 
« Gentian violet and Congo red, as described by Biffen (1). 
Ruthenium red and methyl green, first soaking in a solution of 75 per 
cent, alcohol and 2 5 per cent, hydrochloric acid and washing in 50 per cent, 
ammonia. 
Safranin and Hoffmann’s blue. With this stain after many trials the 
most satisfactory procedure was found to be the following : The sections 
were placed in safranin for fifteen minutes and then washed rapidly in 
50 per cent, alcohol. They were then left in the Hoffmann’s blue for from 
fifteen to twenty minutes and then washed in water. They were then passed 
rapidly up to absolute alcohol, and through xylol, and mounted in Canada 
balsam. 
Lastly, the diamant fuchsin and light green method was tried and 
gave the best results, especially for following the course of the hyphae 
in the tissues. 
Disorganization of the Tissues. 
The portions attacked can be recognized by the discolouration of the 
wood, which assumes a dark grey hue with the large medullary rays stand- 
ing out unchanged (Figs. 30 and 31). Just as Biffen observed with Bulgaria 
polymorpha (1), the medullary rays seem to withstand the attack longer, but 
eventually they too succumb. 
The hyphae apparently disintegrate after they have done their work, 
for where the wood had undergone considerable change (as described 
below), few or no hyphae were to be met with, whereas in places in which 
the hyphae were abundant the decomposition had hardly begun. This can 
be easily seen by comparing Figs. 32 and 33. 
