CHAPTER VI 

 HISTOLOGY AND CHEMISTRY OF FUNGI 



Histology. — Naked cells which are destitute of a cell wall and con- 

 sist of naked protoplasm occur as motile cells in only two unimportant 

 groups of the OOMYCETALES. The cell wall of fungi does not 

 appear from the results of numerous workers upon its chemistry 

 to be of the same nature in the different groups of them. A general 

 term which has been in current use and which was first suggested 

 by A. de Bary is that of fungous cellulose, but that term, as far 

 as indicating the chemic character of the membrane is concerned, is 

 a misnomer. It has its correct application, if we employ the term in 

 the sense of fungous membrane substance. We owe to C. van Wis- 

 selingh (rSgS) the examination of about a hundred species from nearly 

 all of the orders and most of the families of EUMYCETES. Wisselingh 

 could detect the presence of cellulose with certainty only in two families 

 the Saprolegniace^ and the Peronosporace^. This carbohydrate 

 could not be detected either in the ZYGOMYCETALES or in am 

 of the MYCOMYCETES examined, and especially was it found to hi 

 absent in the yeast Saccharomyces cerevisia. The researches o 

 Winterstein, Gilson and Wisselingh proved that chitin formerly sup 

 posed to be of animal origin was found in the membranes of fungi 

 With the exception of the two families mentioned above, the bacteri; 

 and the yeasts, chitin has been detected in all other species of fung 

 examined, e.g., Mucor mucedo, M. racemosus, Rhizopus nigricans 

 Penicillium glaucum, Trichothecium roseum, in the sclerotia of Botryii 

 cinerea and Claviceps purpurea. We do not know at present of thi 

 simultaneous occurrence of cellulose and chitin in the same cell wall 

 E. Winterstein has found true hemicellulose in certain fungi and othe 

 chemic substances have been reported such as carbohydrates of th 

 pentosan group, pectose, callose, etc. 



The outer layers of the wall, in some fungi (TsEMELLACEiE) may b 

 mucilaginous, so that it is resolved into a soft gelatinous mass. Lignifi 

 cation has l)een reported in the large plicated fungi though whethf 



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