THE relation of soil gases to crop production has received considerable attention during the past year, notably in India. In Bulletin No. 52, issued by the Agricultural Research Institute, Pusa, Mr. and Mrs. Howard discuss the ventilation of soils in the great alluvial plains forming the Ganges basin and in the Quetta valley of north-west India. The authors think that, in a country like India, where water is so often the limiting factor in crop production, too little attention has been paid to the importance of continuous gaseous inter-change between the soil and the atmosphere during the growing period. The conclusions reached in this paper are not based on direct experiment, but on long-continued and almost daily observations on the growth of crops. Anticipating criticism on the lack of what they term “ test-tube evidence,” the authors point out that the greatest advances in British agriculture, both as regards crop production and the improvement of stock, have been made by similar methods.