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S. Reginald Price. 
earliest, the wall gradually disappearing from within towards the 
middle lamella, so that there is no separation of the elements. 
In the present work an investigation was made of the earlier 
stages of the destruction of Elm wood induced by the fungus in pure 
culture. 
The hyphas were present in very large numbers in practically 
all the elements, to a depth of 5 to 6 mm., in the older culture 
blocks. The removal of the somewhat leathery mycelial felt from 
the block usually accomplished the removal of some of the 
disintegrated wood on the outside. Sections were cut in various 
directions and at different depths, the staining being usually effected 
by the use of Gossypimine (Cotton Red) and Picric Aniline Blue, or 
of Methyl Green and Congo Red (cf. 5, p. 176). With the first 
combination, the hyphae stain a bright blue and the lignified portions 
of the section red. 
Generally speaking the hyphas were very few at depths greater 
than 6 mm., and were then usually most obvious in the vessels, as 
very fine straight threads. A few hyphae penetrated the elements 
to the middle of many of the wood blocks examined. The medullary 
rays were almost constantly avoided by the hyphae. 
Potter (10) has shown that steam sterilisation may have the 
effect of delignifying the inner walls of some of the elements and 
that there is a considerable amount of cellulose lining the walls of 
the elements in fresh wood. He suggested that a portion of the 
delignification obtained by Marshall Ward (13) in his cultures of 
Stereum hirsutum may have been due to this effect. He, however, 
tried the effect of steaming only on thin sections and not on large 
blocks of wood. Spaulding (12) tried the effect of steaming on 
sections of some American woods, but found on the whole that little 
delignification took place, and he assumed that the delignification 
produced in culture blocks would be negligible. 
For comparison with the culture blocks in the present case, 
blocks of Elm wood, similar to those used for the cultures, were set 
up steam-sterilised as before, and kept for some months in the damp 
atmosphere of the tubes. These blocks were used for comparison 
with the fresh wood, and with the wood attacked by mycelium. 
To study the delignification, sections were treated with chlor- 
zinc-iodine, phloroglucin and aniline chloride, the first of these 
giving the best results. 
The fresh wood of Ulmus shows some cellulose lining the inside 
of the walls of the fibres (10, p. 127). I find it more particularly in 
the fibres associated with the vessels. 
