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no particular difficulty in getting the mycelium to go through all its 
stages to the formation of spores again. I transferred the young 
mycelia from the separation-plates to large flasks containing respec- 
tively, the leaves of grass, pine, beech, oak and fern, and the sawdust 
of pine and of oak, the intention being to compare the growth and 
characters on these media. No difficulty occurred in the early stages ; 
the mycelium “ran” excellently, and all seemed going well up to 
Christmas-time. From then to now, however, although growth con- 
tinues, no further development has been possible. As the failures 
are similar in all cases, I will confine my account to Marasmius, the 
more so since Brefeld and Costantin also failed with this genus. 
I tried these cultures in the dark and in diffuse daylight, as well as 
fully exposed at a window. I tried them at high and low tempera- 
tures, even exposing some sets to winter frost. Some were kept 
moist, others allowed to dry up; some well aerated, others not. To 
some sets of cultures I added certain moulds—Penicillium, As per- 
gillus, or Dematium—in the hope that the quicker decomposition of 
the leaves set up by these Fungi would accelerate matters. All of no 
use, apparently ! In almost every case—nearly 100 cultures were 
tried—the mycelium ran admirably, but when it had formed a well- 
developed white felt-work growth ceased, and nothing further came 
of the matter. There the white felt or spawn remains to this day. It 
is alive, but will not fructify. 
Meanwhile I had also cultivated the mycelium—again successfully 
—on various gelatine and agar media, and obtained excellent strong 
growths on pith saturated with extract of decomposing pine ieaves 
and a little xylose—a sugar obtained from wood—having frequently 
found such pith media very useful, and thinking xylose the most likely 
carbo-hydrate for such a fungus. Again no result. Even after ten 
months I had nothing more than a well-developed sterile mycelial felt. 
One result seemed clear, however, namely, the mycelium grows far 
better on vegetable media than on animal substances, such as gelatine 
with dung extract, which is not surprising when we remember the 
natural habitat of the fungus. It is generally assumed that the Fungi 
on dead leaves, wood, etc., utilise the humus of the forest soil as food- 
material, but Reinitzer has recently shown that purified humus is use- 
less as a source of carbonaceous food even to Penicillium and As per- 
gillus, but that if such humus is added to a suitable carbo-hydrate, 
such as sugar, the former supplies nitrogen to the fungus, whence we 
may infer that my experiment with xylose was not without promise. 
Do the failures mean that this Marasmius, apparently a most pro- 
nounced saprophyte on dead leaves, is really parasitic ? Do its fine 
vegetative hyphee after all play the part of a Mycorhiza, and only 
‘run” on the dead leaves to throw up the pileus, the carbonaceous 
material for which has been stored up after collection from the roots 
of some tree ? At present it seems impossible to say. But the 
failures of Brefeld, Costantin and myself to get this fungus to fructify 
on (in my experiments) the very media on which it is found in Nature 
are significant, and, although negative results prove nothing, warrant 
the questions I have raised. 

