Review : 
3 ^ 
on dead organic substances, from which under suitable conditions 
of moisture, etc., they obtain the nutriment essential both for their 
germination and for their further growth. 
Brefeld shows the important part that herbivorous animals 
play in the dissemination of the spores of Fungi. The animals 
devour various parts of plants on which spores have fallen, the 
spores pass unharmed through the alimentary canal and are voided 
with the fceces, and these provide an extremely favourable medium 
for their germination and the subsequent growth of the Fungi 
resulting from them. In fact with some forms, especially in the 
case of those usually found growing on dung, the passage of the 
spores through the body of an animal seems essential before 
germination can take place. Spores of some coprophilous Fungi 
have however been induced to germinate artificially by sowing them 
in a decoction of dung maintained at a temperature of about 87° F., 
when neither condition by itself sufficed to bring about the required 
result. 
Dung has been found to provide one of the most suitable media 
for cultivating Fungi and a decoction for this purpose is very easy 
to prepare. The decoction may be evaporated down to one-tenth 
of its bulk without deterioration and in this concentrated condition 
it is secure from decomposition by the entrance of chance fungus- 
spores. In this state it may be kept for almost any length of time, 
and may be transported for long distances, e.g., to tropical regions 
where horse-dung is sometimes unprocurable, and when required 
for use may be restored to its original bulk by the addition of water. 
The plan recommended of covering the mouths of flasks in 
which culture-media are kept with two thicknesses of filter-paper, 
the inner one sterilised with alcohol and the outer one with mercuric 
chloride is an improvement on the plugs of cotton-wool generally 
employed for this purpose, as less likely to lead to the introduction 
of particles of dust and other impurities when the flasks are opened 
to remove some of the contents. 
A decoction of plums or other fruit for those fungus-spores 
which require an acid medium for their germination, and the well- 
known beer-wort are other useful culture-media and, like the dung- 
decoction, may be evaporated down to a small bulk and preserved 
in this state until they are required for use. Various mixtures of 
any or all of these may be employed. Meat-decoctions find their 
application in the cultivation of Bacteria and of the Fungi which 
attack insects, e.g., Empusa, Entomophthora, Cordyceps, Laboulbenia, 
etc., and those forms which live on horn-like substances. 
For cultivating parasitic Fungi, the suitability of a nutrient 
medium prepared from those parts of the host on or in which the 
parasites usually live is obvious. Thus, Brefeld obtained an excellent 
growth of Phytophthom infestans with the production of conidia 
by using an extract prepared from potato tubers, and of Nyctalis 
parasitica , which in nature is always found growing on the cap¬ 
shaped fructifications of species of Russula, by the employment of 
a watery extract of the latter. Closely related to this is the 
observation that in nutrient solutions prepared from the fructifications 
of various Basidiomycetes, the spores of these and also of other 
Fungi germinate more readily than in other media. 
One or other of these solutions will usually suffice to bring 
