branches, often partitioned, and larger and more branched than those
observed on the leaves. The appearance of these fertile branches
ordinarily takes place at the end of from twenty-four to forty-eight
hours; sometimes, nevertheless, one must wait for many days. These
phenomena are observed in all the diseased tubercles without
exception, so long as they have not succumbed to putrefaction,
which arrests the development of the parasite and kills it.

Young plants of the species liable to attack may be inoculated with
the conidia of the species of _Peronospora_ usually developed on that
particular host, in the same manner that young cruciferous plants,
watered with an infusion of the spores of _Cystopus candidus_, will
soon exhibit evidence of attack from the white rust.

It is to the cultivation and close investigation of the growth and
metamorphoses of the minute fungi that we must look for the most
important additions which have yet to be made to our knowledge of the
life-history of these most complex and interesting organisms.

[A] Experiments were made at Belvoir, by Mr. Ingram, in the
cultivation of several species of _Agaricini_, but without
success, and a similar fate attended some spawn of a very
superior kind from the Swan River, which was submitted to the
late Mr. J. Henderson. No result was obtained at Chiswick,
either from the cultivation of truffles or from the inoculation
of grass-plots with excellent spawn. Mr. Disney's experiments
at the Hyde, near Ingatestone, were made with dried truffles,
and were not likely to succeed. The Viscomte Noe succeeded in
obtaining abundant truffles, in an enclosed portion of a wood
fenced from wild boars, by watering the ground with an infusion
of fresh specimens; but it is possible that as this took place
in a truffle country, there might have been a crop without any
manipulation. Similar trials, and it is said successfully, have
been made with _Boletus edulis_. Specimens of prepared
truffle-spawn were sent many years since to the "Gardener's
Chronicle," but they proved useless, if indeed they really
contained any reliable spawn.

[B] Robinson, "On Mushroom Culture," London, 1870. Cuthill, "On the
Cultivation of the Mushroom," 1861. Abercrombie, "The Garden
Mushroom; its Culture, &c." 1802.

[C] This has, however, not been conf