6 DIVISION I. — GENERAL MORPHOLOGY. 



several sap-cavities {vacuoles). Comparatively large vacuoles are often separated 

 from one another by thin films of protoplasm, which in elongated cylindrical cells 

 are not unfrequentlv placed across the cell, like transverse septa of cell-membrane, 

 and this position has before now caused them to be mistaken for transverse cell- 

 membranes'. The greater part of the 86-94 per cent, of water, which Sehlossberger 

 and Dopping found in fleshy mushrooms, is to be placed to the account of the 

 watery cell-sap. 



Errera discovered a remarkably large amount of glycogen in the cells of many 

 Fungi. This substance permeates the protoplasm, renders it unusually refringent, 

 ami may be recognised under the microscope by this quality and by the charac- 

 teristic reddish-brown colour which it assumes in the presence of iodine. It occurs 

 especially in the asci of the Discomycetes and Truffles, but Errera found it also 

 in the vegetative cells of some of these Fungi, of some of the Mucorini, and of 

 certain Hymenomycetes, &c. 



Nuclei are found in many cells connected with reproductive processes in the 

 Fungi, in asci for example and basidia, and their relations to the formation of daughter- 

 cells are in some cases at least clearly understood ; but there is some uncertainty with 

 regard to the nuclei in the vegetative cells of the thallus, owing to their minuteness. 

 On the one hand the presence of nuclei in the vegetative cells is probable where they 

 have not been directly observed, because the reproductive cells which have nuclei 

 are formed directly from vegetative cells and are distinguished from them only by 

 their greater size, which may be the only reason why their nuclei are clearly seen, 

 and because the nuclein which is characteristic of cell-nuclei has been shown by 

 macrochemical methods to be present in cells, in which the presence of a morpho- 

 logical nucleus is not or has not been certainly ascertained. In conformity with this, 

 Strasburger with the help of colouring reagents detected nuclei in the cells of the thallus 

 and in the spores of the Saprolegnieae, and Schmitz had previously asserted their 

 existence in a number of other Fungi, as for instance in Oidium lactis, in the 

 Peronosporeae, Mucorini, and Saccharomyces ; to these may be added Penicil- 

 lium glaucum (Strasburger) and especially the gonidial state of Peziza Fuckeliana 

 (Botrytis cinerea). But on the other hand the objects under consideration, except 

 in the Saprolegnieae, are of such minute size, that the satisfactory discrimination 

 of true nuclei from other small bodies contained in the protoplasm, and like them 

 perhaps rendered more distinct by colouring reagents, is extremely difficult, and 

 can only be obtained after renewed investigations. The accounts in our possession 

 make it distinctly probable that the protoplasm of the elongated vegetative cells of 

 the Fungi which have been examined contains several or even many small nuclei, 

 the division and multiplication of which is not in direct morphological connection 

 with the vegetative cell-division. Only the short vegetative cells of Saccharomyces 

 according to Schmitz arc uninucleate. The reproductive cells to which we have 

 referred above have one or more nuclei according to the species; the connection of 

 the nuclei with the formation of daughter-cells, as far as it is known, will be described 

 below along with the phenomena of reproduction. 



The protoplasm of the cells of the Fungi contain no chlorophyll or analogous 



See Reisseck in Botan. Zeitg. 1853, p. 337. 



