d M. de Bornholz give the chief accounts of the
efforts that have been made towards the cultivation of these fungi.
They state that a compost is prepared of pure mould and vegetable soil
mixed with dry leaves and sawdust, in which, when properly moistened,
mature truffles are placed in winter, either whole or in fragments,
and that after the lapse of some time small truffles are found in the
compost.[I] The most successful plan consists in sowing acorns over a
considerable extent of land of a calcareous nature; and when the young
oaks have attained the age of ten or twelve years, truffles are found
in the intervals between the trees. This process was carried on in the
neighbourhood of Loudun, where truffle-beds had formerly existed, but
where they had long ceased to be productive--a fact indicating the
aptitude of the soil for the purpose. In this case no attempt was
made to produce truffles by placing ripe specimens in the earth, but
they sprang up themselves from spores probably contained in the soil.
The young trees were left rather wide apart, and were cut, for the
first time, about the twelfth year after sowing, and afterwards at
intervals of from seven to nine years. Truffles were thus obtained for
a period of from twenty-five to thirty years, after which the
plantations ceased to be productive, owing, it was said, to the ground
being too much shaded by the branches of the young trees. It is the
opinion of the Messrs. Tulasne that the regular cultivation of the
truffle in gardens can never be so successful as this so-called
indirect culture at Loudun, but they think that a satisfactory result
might be obtained in suitable soils by planting fragments of mature
truffles in wooded localities, taking care that the other conditions
of the spots selected should be analogous to those of the regular
truffle-grounds, and they recommend a judicious thinning of the trees
and clearing the surface from brushwood, etc., which prevents at once
the beneficial effects of rain and of the direct sun's rays. A truffle
collector stated to Mr. Broome that whenever a plantation of beech, or
beech and fir, is made on the chalk districts of Salisbury Plain,
after the lapse of a few years truffles are produced, and that these
plantations continue productive for a period of from ten to fifteen
years, after which they cease to be so.

M. Gasparin reported to the jurors of the Paris Exhibition of 1855,
concerning the operations of M. Rousseau