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 



1 Icon, analyt. fungorurn, pp. 12, 25. 



