rorULAR SCIENCE REVIEW. 
are appreciated ; but even amongst the Australian aborigines, 
the natives of Tahiti, the Bhoteans of India, the Malays, and 
others, some fungus is sought after and devoured. It would be 
interesting to ascertain the extent of this fungus-eating pro- 
pensity ill the human race. At present our knowledge is limited 
to a few facts, and these sometimes without even a guess at the 
kind of fungus which is employed as food. 
The large number of species to which we have alluded include 
an immense variety of forms. Between some groups of species 
and others there is as great a difference as between any two 
natural orders of flowering plants. In fact, the popular notion 
of a fungus, as typified in a mushroom ” or a “ toadstool ” 
applies only to a small proportion of the whole. Some are 
larger than the head of a man ; others are smaller than the 
head of a pin. It is not easy to convince the casual observer of 
the affinity between truffles, puff-balls, blue-mould, and corn- 
mildew, or between all these and that privileged kind which 
bears the name, par excellence^ of mushroom,” and is specially 
cultivated for the delectation of epicures. Yet these all consti- 
tute what some call a “ class,” and others an alliance of orders,” 
under the name of fungi. 
Out of two thousand five hundred British fungi, there are at 
least five hundred of the mushroom ” type. By devoting a 
little attention to the structure and anatomy of this one species, 
therefore, we may hope to obtain a key to the structure of five 
hundred other and kindred forms. 
The only fungus cultivated in this country is that known as 
the “ common mushroom,” or, botanically, AgaHcus campestris, 
Fr. In the estimation of some, nothing else deserves the name 
of mushroom, no other merits an attempt at cultivation. This 
is a great mistake, which will be remedied, perhaps, some day. 
All who have attempted to grow even the ‘‘domesticated” 
musliroorn (if such a term may be applied) know that it is 
useless to sow the spores, or water with the spores, or so employ 
tlje spores as they would the seeds of other plants, of which 
these would seem to be the analogues, in the hope of obtaining 
a crop. The seeds may be sown, but the plants are not produced. 
The reason for this fact is accounted for by another. Horse 
droppings, treated almost as seeds, realise in skilful- hands an 
excellent crop. The explanation seems at least plausible and 
in accordance with the evidence. The spores of the mushroom 
will not germinate until they have passed through an animal. 
The horse becomes the medium ; the spores are devoured, 
disjected, and, afterwards germinating in the excrement, appear 
to prove that the horse — or some such condition of heat and 
moisture as the stomach of the horse affords — is essential to the 
reproduction of muslirooms. The earliest condition in which 
