Sept. 1, 1865.] THE TECHNOLOGIST. 
ON TRUFFLES. 81 
obscurity. The fact of the existence of a mycelium in truffles, resenib - 
ling that of mushrooms, must be taken into consideration in any attempt 
that may be made to cultivate them. 
The soils in which edible truffles are found in France are always 
calcareous or calcareous clays, which accords generally with my own 
experience. Tuber mesentericum occurs, how 7 ever, in ferruginous sands, 
as is also the case with another species. Hydnotrya Tulasnei, which, or a 
closely allied kind, is largely eaten in Bohemia, under the name of 
Czerwena Tartoffle. Messrs. Tulasne describe the soil of a truffle district 
near Loudun, Vienne, as composed of rolled fragments of calcareous 
matter, mixed with fine quartzose sands, lying on a thick bed of compact 
marly clay, which easily splits up into thin layers. It contains, in 1,000 
parts, 500 of calcareous matter, 325 of clay and iron, 150 of quartzose 
sand, and 35 parts, more or less, of vegetable mould But they attribute 
a still greater influence in the production of these plants to the presence 
of trees — a condition necessary perhaps to their growth, in order to keep 
off the heat of the direct sun-rays. Our authors testify, indeed, that 
this is not always indispensable ; and I have seen truffles dug up on 
the bare sloping sides of the Italian mountains. 
Some persons have supposed that these fungi are parasitic on the 
roots of trees. This the Tulasnes expressly deny, on the strength of 
observations and inquiries instituted to that end ; and I can confirm 
them in this matter, and would remark that the frequent presence of 
certain galls attached to the small roots of the oaks, resembling young 
truffles so strongly as often to deceive me for a time, may have given 
origin to this error. 
Some trees appear to be more favourable to the production of truffles 
than others. Oak and hornbeam are especially mentioned ; but, besides 
these, chestnut, birch, box, and hazel are alluded to. I have generally 
found Tuber cestivum under beech-trees, but also under hazel, Tuber 
macrosporum under oaks, and T. brumale under oaks and Abele. The 
men who collect truffles for Covent Garden obtain them chiefly under 
beech, and in mixed plantations of fir and beech. The truffle-grounds 
of France are remarkable for the sterility of the surface, the cause of 
which has given rise to many conjectures — viz., that truffles exercise a 
prejudicial influence on all plants in contact with or proximity to them- 
selves, by appropriating their nutriment in a manner similar to the 
Rhizoctonice ; but a more probable reason of this sterility is the frequent 
digging to which the truffle-grounds are subjected by the collectors ; 
for, as truffles are not truly parasitic, it would attribute an inconceivable 
amount of influence to their mycelium to suppose them capable by its 
means of destroying all the surrounding vegetation. And we may 
remark, that some species occur in grassy places, as in the forest of 
Vincennes, according to Tulasne ; and so with T. macrosporum and 
T. brumale, as I find them. It seems to be a better explanation of this 
sterility, so generally accompanying truffles, that they can only succeed 
VOL. VI. ' H 
