214 EXPERIMENT STATION EECOED. [Vol.35 



Siunmit, Boone, Osage, and Bates silt loams cover, respectively, 27.5, 26.9, 12.2, 

 and 11.1 per cent of the area. 



The soils of Antigua, H. A. Tempany {West Indian Bui., 15 (1915), No. 2, 

 pp. 69-102, pis. 8).— This report deals primarily with the physical and chemical 

 characteristics of the soils of an island area of 108 square miles, which topo- 

 graphically is divided into three principal regions: (1) A generally flat central 

 plain, which traverses the island diagonally from west to east; (2) a northeast- 

 ern limestone area consisting of undulating country; and (3) a mountainous 

 southwestern area of volcanic origin. 



The soils of the limestone area approximate very closely to a single 

 physical type in which the particles of the fine silt and clay on the average 

 constitute 65.9 per cent of the soil. " The soils of the low-lying central portion 

 of the island . . . comprise a series of heavy clay soils deficient in calcium car- 

 bonate, requiring thorough tillage and drainage for the maintenance of tilth." 

 The soils of the southern district are ndhcalcareous and well drained, and 

 " approximate fairly closely to one physical tjT)e in which the larger and the 

 smaller particles are nearly balanced." 



Tables showing the mean physical composition of the principal soil types 

 encountered on the island are appended. 



Studies on soil protozoa, S. A. Waksman (Soil Sci., 1 (1916), No. 2, pp. 135- 

 152). — Studies with loam soils of high and low humus content and clay soils 

 on (1) the activity of protozoa in the soil, (2) the numbers and types of 

 protozoa in different soils at different depths, and (3) the effect of protozoa on 

 bacterial numbers and their decomposition of organic matter in the soil are 

 reported. 



It was found that moisture, humus content, and the structure of the soil were 

 the Important factors governing the activities of the protozoa. Sterilization of 

 soil and the addition of easily soluble organic matter made the conditions 

 optimum for protozoan activities at a lower moisture content than the corre- 

 sponding unsterilized or untreated soils. The flag^ellates were the most common 

 soil protozoa found active in the soil with moisture content too low for the 

 development of the other groups. 



" The flagellates are the largest group of soil protozoa ; the greatest number of 

 flagellates ai-e found in the soil just below the surface; the ciliates at a depth 

 of 4 in. ; the numbers decrease with the depth, so that below 12 in. the soil is 

 practically free from protozoa. Soil protozoa do not have any appreciable 

 influence upon the ammonification by bacteria. The presence of protozoa acts 

 detrimentally upon bacterial numbers, so that when the conditions become 

 favorable for protozoa development, the bacterial numbers decrease." 



The spirit of the soil, G. D. Knox (London: Constable & Co., Ltd., 1915, pp. 

 Xin+242, pis. 16).— This book gives a popular account of nitrogen fixation in 

 tlie soil by bacteria and of the production of auximones in bacterized peat 

 according to Bottomloy. It contains chapters on the nitrate problem ; England's 

 food supply in peace and war ; bacteria and protozoa ; peat and its uses ; fixation 

 of nitrogen by leguminous plants; humus; bacterized peat, its preparation and 

 general properties; vitamins, accessory food bodies, and auximones; elementary 

 conceptions of chemistry in relation to tlie soil ; the testing of humogen ; the 

 preparation of humogen; and how humogen is applied. Two final sections' give 

 the results of experience along the above lines. 



It Is the main contention of this book "that soil inoculation scientifically 

 carried out will greatly increase the yield of the land that is already under 

 cultivation, and that it will bring into cultivation large tracts of land that it 

 has hitherto not paid to cultivate, and that by the stimulation of plants it will 



