CHAPTER I.—HISTOLOGICAL CHARACTERISTICS. 13 
points as there are rows of cells. If the sections are kept for a long time in water, 
the delicate bounding lines of the lamellae disappear and the lamellae themselves 
coalesce into a homogeneous mass. 
The above cases establish the occurrence of lamellae of different thickness and 
capacity for swelling in thickened cell-membranes ; but it also follows from the facts 
which have been given, that the apparently homogeneous substance between the cells 
of these Fungi, like the pseudo-intercellular substance in many Fucoideae, Florideae, 
and others, is not to be regarded as a secreted homogeneous substance distinct from 
the cell-membrane, but originates in the close contact and partial coalescence of the 
outer gelatinous thickening-layers of all the hyphae. 
The tissues of many Fungi (Melanogaster, Tremella, Exidia, Guepinia, Dacryomyces, 
Bulgaria, Thelephora mesenterica, Mitremyces, Cyttaria, Panus stypticus), the peridia 
of the Phalloideae, young Nidularieae, the surface of many Hymenomycetes, as Agaricus 
Mycena sect. Glutinipedes, Fr., Amanita muscaria, Boletus luteus, and many others, 
are of gelatinous constitution, and agree in structure with those of Calocera, Hysteran- 
gium and other forms described above; but the interstitial gelatinous substance 
appears in most cases to be really a homogeneous mass, and has not yet been 
separated into portions belonging to the individual cells. This may perhaps yet 
be done in many of these forms; at the same time it would appear from the 
published observations on Calocera and from the close affinity and agreement in 
structure between Calocera, Guepinia, and Tremella, and between Hysterangium 
and Phallus, &c., that we are justified in considering the homogeneous gelatinous 
substance of all the Fungi mentioned above as simply a product of the coalescence 
of soft gelatinous thickening-layers of the cell-membranes. H. Hoffmann seems to 
take this view}, as he speaks of the gelatinous substance in the outer portions of 
the pileus of the fleshy Hymenomycetes as a product of the deliquescence of the 
membrane. 
The threads of the capillitium in all species, as it would seem, of Lycoperdon 
(L. pusillum, L. Bovista, L. giganteum; see Division II) are delicately pitted. The 
thick transverse walls of Dactylium macrosporum, Fr. which are formed of two 
semi-lenticular lamellae have the large pit in their centre, just in the same way as 
it occurs in the transverse walls of filiform Florideae like Callithamnion. I have 
never seen similar pits in other Filamentous Fungi ; their transverse walls are usually 
delicate, and in some cases, as in Botrytis cinerea, they appear to be thinner in the 
centre than at the margin. 
Fungus-cellulose. In my first edition I gave the name of Fungus-cellulose to 
the substance of the greater part of the non-gelatinous membranes of the Fungi for 
the reasons given above. C. Richter has recently arrived at the conclusion that there 
is no special modification of cellulose requiring to be distinguished by such a name, 
and that the membranes supposed to contain it are composed of ordinary cellulose 
with foreign, possibly albuminoid admixtures. He shows that the membranes of 
Fungi like Agaricus campestris, Claviceps, Polyporus spec., Daedalea quercina, and 
Cladonia, which do not show the characters of ordinary cellulose even when treated 
in the customary manner with boiling solution of potash, Schulze’s solution, or chromic 
acid, if subjected to longer maceration in a 7-8 per cent. potash solution do give the 
ordinary reactions of cellulose, turning blue with iodine and sulphuric acid and with 
Schulze’s solution, and being soluble in ammoniacal solution of cupric hydrate. The 
maceration must continue for at least 2-3 weeks, sometimes, as in Daedalea, for 
as many months. These observations are a welcome confirmation of the near 
affinity of the substance of the membranes of the Fungi to ordinary cellulose which was 
indicated by macrochemical analysis; but they merely prove that the membrane of 
these Fungi is altered by maceration with potash in the way described. Whether 

* Icon. analyt. fungorum, pp. 12, 25. 
