HEART-ROT 97 
preparations for making observations on these patches were 
obtained by first soaking sections in dilute HCl until 
bleached, then staining with safranin and mounting in 
Canada balsam. The 
hyphal walls, which were 
previously dark brown, 
readily absorb the saf- 
ranin, whilst those which 
were formerly colourless 
remain so. In sections 
mounted in this way the 
following details may be 
observed. 
As shown in fig. 35, the 
hyphae at the edge of 
the dark patch are easily 
distinguishable, though 
frequently two or three 
may be seen growing side 
by side in fascicles and 
touching for their whole 
length. They grow in 
this way up and down 
the tracheides and along 
the medullary rays. 
Nearer the middle of the 
black patch the hyphae 
are very irregular, with 
swellings here and there ; Fig. 35.—Longitudinal section near 
and where two hyphae the edge of a black speck, after bleach- 
are touching, the inter- ing in dilute hydrochloric acid: b, bore- 
‘ hole; h, two hyphae joined by the disso- 
mediate walls have often lution of their adjoining walls ( x 800). 
been partially or wholly 
digested, so that several adjoining hyphae come to have 
the appearance of one very large hypha (fig. 35, ). 
In the centre of the patch still further disorganization is 
found. The walls of some hyphae break down entirely, 
setting free a jet black liquid which stains all the contents 
1888 1 
