346 Marshall Ward. — On a lily -disease. 
I now pass to the consideration of the second of the two 
statements on p. 339, viz. that aqueous extracts of the my- 
celium contain a ferment which swells and dissolves cellulose. 
On reflection it seemed probable that if the ‘ ferment-drops’ 
really contained the ferment, then, since the hyphae exuded 
the drops into the Pasteur’s solution and other liquid media, 
one ought to be able to detect it there by its action on the 
tissues 1 ; in other words, if the extruded drops contain a fer- 
ment which dissolves cellulose, then the liquid containing the 
ferment ought to have a solvent action on cellulose. 
My first experiment met with decided success, so far as it 
went, for on placing thin sections of the bud of a lily in a few 
drops of the Pasteur’s solution in which the fungus had been 
growing for several days, they underwent a distinct alteration 
in the course of the night, whereas similar sections in the same 
liquid, treated similarly except that it was boiled for two 
minutes, underwent no such change. The alteration con- 
sisted in a decided swelling and softening of the cellulose of 
the cell-walls, rendering their stratification remarkably distinct, 
and causing them to refract the light in a peculiar manner 
(see Figs. 59 and 66 ). 
Since I could not be sure that such a solution was, so to 
speak, quite clean, or entirely devoid of other organisms, it 
became necessary to start a series of pure cultures on a larger 
scale to see if the phenomenon was a constant one. 
After trying several methods, I finally adopted the follow- 
ing one as giving the best results on the whole. Flasks of 
about half a litre capacity were selected, washed, and heated 
on a sand-bath ; when cool, they were carefully charged with 
about a quarter of a litre of the solution to be used — Pasteur’s 
solution, with or without peptone, sterilised cold-water extracts 
of raisins, lily-bulb, etc. — and at once placed on a sand-bath, 
and the liquid boiled for 10-15 minutes ; the neck was stopped 
1 A ferment which causes the swelling and alteration of cellulose was found by 
De Bary in Peziza Sclerotiorum (Bot. Zeit. 1886, Nos. 22-27), of which more 
shortly, and by Beyerinck in the Gumming of Trees under the influence of Cory- 
neum Beyerinckii (Archives Neerlandaises, T. xix (1884), p. 43). 
