656 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Fungi. 
Composition of the Cell-wall of Fungi.* * * § — Herr C. van Wisselingh 
has made a careful examination of the chemical nature of the cell-wall 
in more than 100 species of Fungi, belonging to all the more important 
families. His general conclusion is, that while cellulose occurs but rarely, 
chitin is a substance of very wide distribution, and is identical with the 
chitin found in animals. Cellulose was found in Fungi belonging to 
the Myxomycetes ( Didymium squamulosum), Peronosporeae ( Plasmopara 
densa , Cystopus Portulacee), and Saprolegniacese ( Saprolegnia dioica). 
Chitin occurs in the Myxomycetes ( Plasmodiophora Brassicse ), Chytri- 
diaceae ( Synchytrium Taraxaci). Entomophthoreae ( Empusa Muscse'), 
Mucorineae ( Mucor Mucedo, Clilamydomucor racemosus , Pilobolus crystal- 
linus ), Rhizopeae ( Bhizopus nigricans ), and in almost all the higher 
Fungi. In a few cases (bacteria, Saccharomyces Cerevisise , Fnligo septica , 
Cetraria islandica ), neither substance occurred ; in no case could the 
presence of the two substances simultaneously in the cell-wall be de- 
termined. Chitin is not so abundant in the reproductive as in the 
vegetative organs, and in thin-walled spores may be replaced by my cosin. 
The chitin is often limited to a definite part of the cell-wall, as occurs 
in many spores. It is commonly accompanied by other little-known 
substances, as lichenin, and two others hitherto undescribed, which the 
author names usnein ( Usnea barbata) and geasterin ( Geaster fornicatus). 
The author believes that the chemical nature of the cell- wall may be 
turned to account in the systematic classification of Fungi. 
Mineral Food-Material of Fungi-t — Herr E. Gunther finds a good 
nutrient solution for fungi to contain necessarily a salt of potassium and 
one of magnesium, and a sulphate and phosphate. A high concentration 
of the solution retards the growth of the fungi. Potassium cannot be 
replaced by sodium, lithium, rubidium, caesium, or copper, except that 
rubidium may replace potassium with Botrytis cinerea. Magnesium 
cannot be replaced by calcium, strontium, barium, beryllium, zinc, or 
cadmium ; salts of these elements are injurious in various degrees, in the 
order named. Salts of copper, when very dilute, promote the growth of 
fungi, but when more concentrated are poisonous. 
Formation of Diastase by Fungi, if — From experiments made on 
Penicillium glaucum and Aspergillus niger, Herr J. Katz comes to the 
conclusion that these fungi have the power of forming diastase, the 
presence of starch not being absolutely necessary for this process. The 
presence of grape- or caue-sugar checks the formation of diastase, but 
the sugar is inverted. In the case of cane-sugar, 1 -5 per cent, prevents 
the formation, while as much as 10 per cent, of milk-sugar is required. 
Bacillus megaterium presents very similar phenomena. The continual 
removal of the diastase as formed promotes the production of fresh 
quantities. 
Fungi producing Citric Acid.§— Herr C. Wehmer finds that Peni- 
cillium luteum is capable of producing citric acid, to the extent of 2-3 per 
* Jahrb. f. wiss. Bot. (Pfeffer u. Strasburger), xxxi. (1898) pp. 619-87 (2 pis.). 
f ‘ Beitr. z. mineralischen Nahrung d. Pilze,’ 59 pp., Erlangen, 1897. See Bot. 
Centralb! , lxxv. (1898) p. 194. 
+ Jahrb. f. wiss. Bot. (Pfeffer u. Strasburger), xxxi. (1898) pp. 599-618. 
§ Chem. Zeit., xxi. (1897) pp. 1022-3. See Journ. Cliem. Soc., 1898, Abstr., 
ii. p. 446. 
