516 EXPERIMENT STATION RECORD. [Vol.37 



sists primarily of determining the relation of relief to soil characteristics on 

 everj' section of a field. The soil characteristics are determined by the mor- 

 pholep' ; botanical growths ; the relation of climate to soil temperature and 

 moisture; and physical, mechanical, and chemical composition. 



The degradation of the chernozems of the western part of the Northern 

 Caucasus, S. A. Iakovlev (Pochvoifedfen'ie {P^dologie), 16 {1914), Xo. 4< PP- 

 1-20; n (1915), No. 1, pp. 1-35). — The chernozem soils of the region are dis- 

 cusseil with reference to mechanical and chemical composition. 



Soil flora studies. — I, The general characteristics of the microscopic flora 

 of soil: II, Methods best adapted to the study of the soil flora, H. J. Co.nn 

 (New York State Sta. Tech. Bui. 57 (1917), pp. 5-42).— This is the first and 

 second of a series of five reports on a study conducted for eight years on the 

 microscopic flora of various New York State soils, in which determinations of 

 the total number of bacteria have been made by the plate method. About 1.000 

 pure cultures of difi'erent organisms were isolated and their general character- 

 istics studied. 



Nonspore-forming bacteria (mostly immotile rods) were found to be the most 

 abundant of all soil microorganisms. Next to them in abundance were the vari- 

 ous types of Actinomyces. Certain spore-forming bacteria were also found, but 

 not in great numbers and apparently they are not of great importance in normal 

 soil. It is thought that soil bacteria are quite different from tho.se found in 

 milk, cheese, or water and that soil has its own characteristic bacterial flora. 



A discussion of the methods used in these studies, the reasons for using them, 

 and their possible development is also includeil. 



Soil flora studies. — III, Spore-forming bacteria in soil, H. J. Con.n (New 

 York State Sta. Tech. Bui. 58 (1917), pp. 5-/6'. figs. 4).— This is the third of 

 the reports of studies on the flora of New York soils and deals with the siwre- 

 forming bacteria of soil. 



"Certain spore-forming bacteria are always found In soil, but in compara- 

 tively small numbers. The three most abundant sjiore formers found In the 

 soils Investigated are Bacillus megatherium, B. mycoides. and B. cereus. B. sim- 

 plex occurs in somewhat smaller numbers. Occasionally other spore-forming 

 bacteria have been encountered, but not in large enough numbers to be con- 

 sidered important. 



" In the past, the spore-forming bacteria have been considered important soil 

 bacteria. The technlc used in this work, however, shows that they comprise 

 but a .'jmall part of the flora and apparently occur in normal soil only in the 

 form of spores. This Indicates that they are ordinarily inactive in soil." 



Soil flora studies. — IV, Nonspore-forming bacteria in soil, H. J. Conn 

 (New York State Sta. Tech. Bui. 59 (1917), pp. 5-iS).— This is the fourth of the 

 reports of studies on the soil flora of New York soils and deals with the non- 

 spore-forming bacteria in soil. 



" The majority of colonies on culture plates made from soil /are those of 

 nonspore-forming bacteria. The only nonspore former that has been success- 

 fully identified with previously described species is P.seudomona.'i fluorescent. 

 This organism is most abundant in freshly aerated soil or in soil to which 

 organic matter has been recently added. It is known to cause ammonification 

 in pure culture, and is therefore thought to take part In the decomposition of 

 organic matter in soil. There are other liquefying nonspore formers in soil 

 that seem to be closely related to P. fluorescens. Thoy increase in numbers 

 under much the same conditions and are thouj:lit to have similar functions. 



"The great majority of the asporogenous bacteria of soil grow so poorly in 

 ordinary laboratory media and produce such small noncharacteristic colonies 

 ou culture plates that little is known about them. One of the greatest present 



