630 EXPERIMENT STATION EECORD. 



materials rendered available by the heating of the soil serve as nutrients for 

 the fungi, and the distillation of heated soil extract does not remove the prop- 

 erties favorable to the growth of Pyronema. 



It was found impossible to render unheated soil favorable to the growth of 

 the fungus by the introduction of the extract of heated soil, and this was 

 apparently due to the fact that the nutrient materials in the extract were 

 i-endered insoluble by the action of the unheated soil. 



Not only was Pyronema readily grown in the extract from the heated soil, 

 but other fungi as well, fungi of various kinds readily growing in soils sub- 

 jected to steam or dry heat. 



Mycological studies on flax and hemp retting, O. Vakga and J. Csokas 

 (Kis&rlet. Kozlem., 13 (1910), 'S^o. 1, pp. 50-52). — ^After a summary of the 

 present methods of retting flax and hemp, the author gives the results of ex- 

 periments on the causes that underly the retting process. 



Retting seems to be a fermentation process due to certain anaerobic bacteria 

 dissolving the pectin substances which bind together the cells of the bark 

 pai'euchyma. These micro-organisms both morphologically and physiologically 

 resemble Stormer's Plectridiuvi pectinovorum. 



Pure cultures of this Plectridium on sterilized flax stems and in the absence 

 of oxygen produced the normal retting. The water retting of hemp was also 

 found to be due to a similar micro-organism, while the dew retting of hemp 

 seems to be produced by various molds, among which a Cladosporium species 

 is the most frequent. 



A study of some of the changes occurring in prunes, Stoykowitch and 

 Bkocqrousseu (Rev. Gen. Bot., ,22 (1910), Xo. 2o-'i, pp. 70-79). — The authors 

 have made a study of prunes to determine some of the causes for their de- 

 preciation. They have found that the principal changes are due to various 

 organisms, among them, yeasts, Monilia, and several species of molds. 



A study was made of the different fungi, and the white discoloration, which 

 is very common, is said to be due to a species of yeast, which depreciates the 

 value of the prunes to a considerable extent. This yeast may be killed by 

 heating the prunes to 65° C. during the process of drying. The most serious 

 changes are those produced by the molds, of which PeniciUiuin glaucum is one 

 of the most common. This reduces the sugar and acid content by nearly 50 

 per cent and causes an increase in the nitrogen. Similar, though less exten- 

 sive, changes are caused by Aspergillus and Khizopus. 



It is claimed that the presence of these molds may be controlled by the rapid 

 reduction of the water in the fresh fruit. 



Monascus purpureas in silage, R. E. Buchanan (Mycologia, 2 (1910), No. S, 

 pp. 99-108, pis. 2, figs. 2). — During 1909 the author made an examination of 

 molds occurring on silage not properly prepared, such silage having in several 

 instances been considered the cause of the death of horses with symptoms of 

 equine cerebro-spinal meningitis. Cultures were made and a number of molds 

 isolated, among them several species of Penicillium, Aspergillus, Mucor, and 

 in one instance Monascus. In this sample of silage the Monascus was prac- 

 tically the only mold found, and as no record was found of the occurrence of 

 this fungus in America or in silage, considerable attention was given to its 

 morphology and cultural characters. 



Several species of Monascus have been described, but the specimens studied 

 seem to Correspond in all essential characters with M. purpurens, and the 

 organism is tentatively placed with that species. The type of this species is 

 said to be common in eastern Asia, where it is used in the preparation of a 

 food product from rice, but without any poisonous effect so far as known. 



