CURRENT LITERATURE 
NOTES FOR STUDENTS 
Metabolism of fungi.—The problem of the necessity of calcium for cts 
has been attacked in different ways by Hort and by Mlle. Ropert. Horr 
relied on removing the calcium from his solutions by precipitating it by means 
of an oxalate. To a solution of ‘‘ame” (rice treated with malt extract) in 
bouillon, he added potassium sulphate and potassium oxalate. In the solution 
thus obtained Aspergillus niger, A. flavus, and Penicillium glaucum developed 
well, while Cephalothecium roseum, Rhizopus nigricans, Rammularia Citri, 
Botrytis tenella, Sclerotinia Libertiana, and a species of Entomophthora developed 
poorly or not at all. All the fungi developed well in the same solution to which 
potassium sulphate but no oxalate had been added. From the fact that a 
number of the fungi did not develop in a solution containing 0.5 per cent of 
potassium oxalate, the author concludes that these probably require calcium 
for their development. The conclusion is scarcely justified, since it is not at 
all probable that calcium is completely removed by potassium oxalate from 
solutions containing organic substances. The same criticism applies to the 
experiments of WEIR, which have already been reviewed in this journal.? 
The problem has been attacked in a more critical manner by Mlle. 
RoBeERt,3 who worked with Aspergillus niger. She showed that the results of 
the earlier investigators (RaAuLIN, Mouiscu, Lorw), who came to the general 
conclusion that calcium was not necessary for the life of most fungi, were due 
to the fact that they relied on the so-called “pure salts” of commerce. Mlle. 
Rosert finds that these “pure salts” always contain calcium. It is thus 
evident that the conclusion generally reached by those investigators, that 
calcium is not necessary for the life of fungi, was reached on insufficient grounds. 
Mlle. Rosert purified the salts she used until no traces of calcium could be 
detected in them. In culture solutions made from such purified materials 
Aspergillus niger grows equally well whether calcium is added or not. From 
dilute solutions containing up to 2. 5 mg. per 250 cc. of solution, the calcium is 
removed almost quantitatively by the fungus and can be recovered in the ash. 
From stronger solutions containing 10-100 mg. per 250 cc. about 80 per cent 
of the calcium is removed. When much calcium is absorbed, both the yield and 
* Hort, S., Haben die héheren Pilze Kalk nétig? Flora 101: 447, 448. 1910. 
* Bor. Gaz. 53:88. 1012. 
T, Mixe., Influence du calcium sur le développement et la composition 
capes ae) P Aspergillus niger. Compt. Rend. 153:1175-1177. 1911 
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