30 
HOLTBRMANN : FUNGUS CULTURES 
As has already been mentioned, the solution contains, 
besides sugar, other organic compounds, including proteid. 
The proteid is not indeed present in such quantity as 
to coagulate on heating, but its composition is apparently 
altered, for in the solution sterilized only by means of the 
autoclave many spores failed to germinate. 
Just as is the case with the bacteria, there is no universal 
nutritive solution for fungi. It has long been well known 
that many spores, e.^., those of Coprinus and other copro- 
philous fungi, can only be cultivated on a decoction of 
dung. It has been noticed, in the course of my experiments, 
that a considerable number of dung-inhabiting fungi will 
germinate easily in my solution, if there be added to it a 
small proportion of meat extract, about 2 gm. to 50 gm. 
of the solution. The mycologist in the tropics cannot be 
too strongly advised to prepare a dung solution in Europe 
and take it with him for all purposes. I have easily 
succeeded in making such a solution in the Berlin Institute 
under great pressure (3-4 atmospheres) in an autoclave. 
The method has been long since described by other authors ; 
horse dung is placed in a vessel with about one-third of its 
weight of water, and heated for about a quarter of an hour 
under the pressure mentioned. The solution is filtered and 
sterilized in the flasks to be described below. In these it 
can be easily carried without fear of contamination. 
Provided with these two solutions it is possible to under- 
take in the tropics many interesting developmental investi- 
gations of the fungi. 
There are many fungus forms in the tropics which cannot 
be brought to germinate by the means at present available, 
e.^., the Phalloideæ, most Clavarieæ, the red-spored Basi- 
diomycetes, &c. With these I had no success. A satis- 
factory explanation of this passive behaviour towards all 
the nutritive solutions employed is not at present forth- 
coming. Nevertheless, I would urge further investigation 
