ABSTRACTS 557 



nitrogen content gave the lowest bacteria counts probably because of 

 the high acidity and large amount of undecomposed matter. The num- 

 bers of bacteria in the soils studied were not governed either by the 

 moisture content of the different soils, or by the nitrogen and carbon 

 contents. 



The greatest number of bacteria were found at a depth of 1 inch in 

 the soils that are under shade the year around. The garden soil gave 

 on the average the largest numbers 4 inches from the surface. The 

 numbers of organisms decreased regularly from a depth of 1 inch down 

 to a depth of 30 inches. 



Three soils showed a regular decrease in the lime requirement down 

 to 30 inches and in all soils this was accompanied with a more or less 

 gradual decrease in the nitrogen and carbon content. 



Frozen soil, though showing a high bacterial content, did not give 

 the largest bacterial numbers found through the year. — Z. N. 



The Inoculation and Incubation of Soil Fungi. Nicholas Kopeloff- 



(Soil Science, 1916, 1, 381-403.) 



The fungi employed in these studies were isolated from soil on the 

 College Farm. They were identified as Rhizopus oryzae (Wendt), 

 Zygorrhyncus vuilleminii (Namyslowski) , Rhizopus nigricans (Ehren- 

 berg), Penicillium sp. 10. Spores of these fungi were obtained for use 

 by growing them on Cook's No. II fungi medium. Suspensions of a 

 known number of spores of each fungus were added to 100 gm. portions 

 of soil of an optimum moisture content to which dried blood and cotton- 

 seed meal were also added. Ammonia determinations were made at 

 the end of 7 days. 



An increase in the number of fungus spores inoculated into the soil 

 was found to be related to a proportional increase in ammonia accumu- 

 lation but this increase was not proportional beyond a certain limit. 



Under the conditions of moisture and temperature employed, cot- 

 ton-seed meal appears to be the more acceptable source of food for the 

 organisms studied. A 7-day incubation period may be recommended as 

 most desirable for the study of soil fungi other than those belonging to 

 the Penicillium group. 



A striking increase in ammonia production was observed to take 

 place every other day (after the first five days). This leads to the con- 

 clusion that the production of ammonia is dependent on the meta- 

 bolic processes of the fungus rather than the biological stage of spore 

 production and germination — Z. N. 



Studies on the Decomposition of Cellulose in Soils. I. G. McBeth. 



(Soil Science, 1916, 1, 437-486.) 



Detailed directions are given for the preparation of cellulose for cel- 

 lulose agar. The action of cellulose-dissolving organisms was studied 

 not only on typical cellulose such as is found in filter paper or in cotton 

 fiber but on the cellulose of plant tissues freed from encrusting sub- 

 stances. The method for preparation of this plant cellulose is given 

 in detail. 



