CULTIVATION. 261 
oaks. It is remarked that the trufiles produced from these 
are larger but less regular than those of the evergreen oak, 
which are smaller, but nearly always spherical. The truflles are 
gathered ab two periods of the year; in May only white truflles 
are to be found, which never blacken and have no odour; they 
are dried and sold for seasoning, The black truffles (Zule. 
melanosporum) commence forming in June, enlarging towards 
the frosty season; then they become hard, and acquire all their 
perfume. They are dug a month before and a month after 
Christmas. It is also asserted that truffles are produccd about 
the vine, or at any rate that the association of the vine is 
favourable to the production of truffles, because truffle-plots near 
vines are very productive. The observation of this decided 
M. Rousseau to plant a row of vines between the caks. Tho 
result of this experiment altogether docs not appear to have 
been by any means flattering, for at the end of eight ycars only 
little more than fifteen pounds were obtained from a hectare of 
land, which, if valued at 45 francs, would leave very little profit. 
M. Rousseau also called attention to a meadow manured (sic) 
with parings of truffles, which was said to have given prodigious 
results. 
The cultivation of minute fungi for scientific purposes has 
been incidentally alluded to and illustrated in foregoing chapters, 
and consequently will not require such full and particular details 
here. Somewhat intermediately, we might allude to the species 
of Sclerotium, which are usually compact, externally blackish, 
rounded or amorphous bodies, consisting of a cellular mass of 
the nature of a concentrated mycelium. Placed in favourable 
conditions, these forms of Svlerotium will develop the peculiar 
species of fungus belonging to them, but in ecrtain cases the 
production is more rapid and casy than in others. In this 
country, Mr. F. Currey has been the most successful in the cul- 
tivation of Sclerotia. The method adopted is to keep them in 
a moist, somewhat warm, but equable atmosphere, and with 
patience await the results. The well-known ergot of rye, wheat, 
and other grasscs may be so cultivated, and Mr. Carrey has 
developed the crgot of the common reed by keeping the stem 
