1911] CURRENT LITERATURE 4g1 
Physiological behavior of Hypocrea rufa.—MepIscu® has made a physi- 
ological study dealing mainly with the factors influencing the production of 
pigment by Hypocrea rufa, and the behavior of the fungus toward ammonium 
salts, nitrates, and nitrites as sources of nitrogen. The conidia of this fungus 
are green when grown on alkaline media, while in acid media yellow conidia are 
produced. When the fungus is grown in liquid media containing only glucose, 
the pigment diffuses into the medium, while the mycelium remains colorless. 
The medium passes through shades varying from green to yellow, orange, and 
brown. Certain salts, as the chlorides of magnesium, sodium, and potassium, 
potassium chlorate, and magnesium sulphate, have a specific stimulating effect 
on the production of pigment. This stimulation is limited for all these salts 
to isotonic solutions varying from 0.05 to 0.125 gram-molecules per liter. No 
pigment is produced in the presence of ammonium salts of strong acids, owing 
to the accumulation of free acid. The pigment production is regarded as an 
oxidation process, as it takes place only in the presence of oxygen, and the 
colored solution can be decolorized by reducing substances like sodium sul- 
phite, hydrogen peroxid, and sodium hydrogen sulphide. The addition of 
an excess of calcium carbonate, infusorial earth, kaolin, and similar substances, 
decreases the intensity of color, probably as a result of absorption. 
fungus grows with either ammonium salts, nitrates, or nitrites as a source of 
nitrogen. Nitrates are reduced to nitrites. With ammonium salts of strong 
acids, growth is soon depressed, and the formation of conidia is inhibited. As 
the fungus has no invertase, it cannot use cane sugar; however, in the presence 
of ammonium salts cane sugar serves as a source of carbon, owing to its inversion 
by the liberated acid. When nitrites are given as the source of nitrogen, 
conidia are produced only in the light, except when levulose is present. In 
that case, a few conidia are produced also in the dark. Ammonium salts are 
utilized in preference to nitrates, and ammonium salts of organic acids in 
preference to those of stronger mineral acids. Experiments to determine if 
the fungus assimilates free nitrogen did not give definite results. The paper 
contains a great number of data on the interaction of various substances in 
nutrient media in which fungi are growing. —H. HASSELBRING. 
Peroxidase and respiratory chromogens.—A number of experiments to 
test the various methods of preparing peroxidase have been performed by 
PALLADINE and IRAKLIONOFF,%} who find that the best method with tissues 
containing small quantities of proteins, as watermelon, pumpkin, etc., is to 
extract with water or 10 per cent NaCl, and precipitate the proteins with 
saturated aqueous HgCl. The enzyme is then precipitated from the purified 
filtrate with 95 per cent alcohol. The best solvent of the precipitated enzyme 
# Mepiscu, Marc, Beitrige zur Physiologie der Hypocrea rufa (Pers.). Jahrb. 
Wiss. Bot. 48:591-631. Igt0. 
33 PALLADINE, W., and IraKLionorr, P., La peroxydase et les giao respira- 
toires chez les ientea Rev. Gén. Botanique 23:225-247. 1911 
