728 EXPERIMENT STATION EECORD. 



ment. The general nature of molds, yeasts, and bacteria, and tlie action and 

 use of beneficial forms are described. Chapters are given on the preserva- 

 tion of food, use of preservatives, canning, etc., as well as on disease bacteria, 

 disinfection, etc. Directions for laboratory experiments to be carried on in 

 connection with courses are also given. 



A laboratory guide in soil bacteriology, J, G. Lipman and P. E. Brown 

 {1911, pp. IV +81, chart 1). — This little book consists of 55 exercises on soil 

 bacteriology, and is designed by the authors to follow courses in general 

 bacteriology and technique. Chapters are given on the preparation of media, 

 methods of determination, and a descriptive chart for the recording of cultural 

 and morphological characteristics of organisms. 



Fungus flora of the soil, C. N. Jensen {l!few York Cornell 8ta. Bui. 315, pp. 

 415-501, figs. 35). — This gives the results of a study of the fungus flora of 

 the soil, made as a partial fulfillment of the requirements for the degree of 

 doctor of philosophy in Cornell University. After a historical sketch of the 

 subject the author describes methods of taking soil samples and isolating 

 and cultivating the organisms. The major portion of the bulletin is taken 

 up with taxonomic descriptions of the different forms. 



The fungus flora of the soil was found to consist of obligate saprophytes 

 and facultative parasites, the former being by far the more abundant. Ac- 

 cording to the author a fungus should not be considered as belonging to the 

 soil flora unless it has been dii'ectly isolated or has been shown under con- 

 trol experiments to live in the soil. In this comiection he demonstrated that 

 Phoma hetw, one of the causes of root rot of sugar beets, winters on the seed 

 balls and not in the soil, while Pythium debaryanum and Aplianomyccs Iwvis, 

 other organisms which attack the sugar beet, winter as saiu'ophytes in the 

 soil and not on the seed balls. 



The presumable facultative parasites and the obligate saprophytes de- 

 termined number 132 species and varieties, many of which are recognized 

 as a cause of injury to economic plants. 



A study was made of the effect of sulphur on the fungus flora of the soil, 

 but 3 months after its application the soil yielded the same species of fungi 

 as did samples which had received no application. 



Bacteria and other fuugi in relation to the soil, D. Rivas (Contrib. Bot. 

 Lab. Univ. Pcnn., 3 (1911), Xo. 3, pp. 2-'t3-21Jt, fig. i).— The author investigated 

 the numbers and activities of about 28 kinds of bacteria, 2 of cocci and 10 of 

 molds found in soils at 12 stations, and reports the following results and 

 conclusions : a 



The bacterial contents of the soil were found to vary according to season, 

 being least from November to February and increasing thereafter to a climax 

 in September or October. These soils are found to be very rich in bacteria 

 producing diastatic, inverting, and proteolytic ferments which are especially 

 adapted for digesting carbohydrates and proteids and which, by changing them 

 into glucose and peptones, respectively, render this raw organic matter into 

 assimilable substances. There is thought to be good reason to assume that this 

 already elaborated food material is, through the agency of bacteria, thus made 

 ready for absorption by the i*oot system and for the nutrition of the plant. 

 It is held, therefore, that not alone are water and salts in solution taken up 

 by the root system of the plant but also already elaborated food, such as 

 glucose, and further that such food, in addition to supplying energy and 

 nourishment to the plant, may become a constituent of the protoplasm and may 

 form organized structures, waste products, and reserve materials, this whole 

 process thus resembling in essentials the process of assimilation in animals. 

 Photosynthesis or auto-assimilation by the plant is not thought to explain all 



