l86 ^ JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



elsewhere. The plants affected were mainly agricultural crops, viz. 

 wheat, oats, rye, and mangolds, but potatos also suffered. The 

 disease, which is known in some parts of Warwickshire as " Maysick," 

 is characterized by the fact that in circular patches or in straggling 

 lines the plants turn yellow in the leaf and almost cease to grow, 

 and in consequence yield a poor crop or none at all. 



The trouble is probably due to the inter-relation between the 

 protozoa and bacteria of the soil. 



A series of experiments was commenced in 1910 and continued 

 during the two seasons following to investigate the action of {a) quick- 

 hme and (b) sulphur on " Maysick " soil. It was found that, whilst 

 quicklime was of no value, sulphur prevented the disease. It would 

 seem, however, that one may easily use too much sulphur. On a plot 

 of wheat which Lad been dressed with 8 cwt. of sulphur per acre before 

 sowing " many plants died, no doubt owing to the heavy dressing of 

 sulphur." A dressing of 6 cwt. per acre is recommended. 



The beneficial effects ul sulphur were even more marked with 

 potatos than with cereals. — A. 5. 



Soils, Persistence of Bacteria in Old Dried. By L. T. Sharp 

 {Plant World, vol. xvi., pp. 101-115). — It has been known for some 

 time that the spore-forming bacteria, moulds, and yeasts, cyst- 

 producing protozoa, and thick-walled cells in general show high resistant 

 powers under different conditions of treatment. Soils exhibit an 

 extreme complexity of chemical and physical conditions, and a great 

 diversity in the number and species of their micro-flora, and therefore 

 offer an unusually good field for the investigation of the resistance 

 of organisms to desiccation, which is a subject of considerable practical 

 importance, especially in the arid regions of the world. The significance 

 of desiccation in general bacteriological practice is apparent in the 

 preservation of various articles of food by drying, and in the transfer 

 of dairy starters, yeasts, and cultures of Bacillus radicicola on dried 

 media, though the manufacturers guarantee the vitality of their dried 

 cultures for only a few months. Previous observers have shown that 

 while soils kept air-dry for two years contain only about one-fifth of 

 the original number of bacteria, the rate of action (production of 

 carbon dioxide, ammonia, &c.) on peptone and urea solutions was more 

 rapid when the solutions were inoculated with soils previously air- 

 dried than with moist soils, and Russell and Hutchinson suggest that 

 the drying of the soil diminishes to a large extent the number of 

 protozoa, which had been feeding on the bacteria, this elimination of 

 competition enabling the bacterial processes to gain superiority when 

 sterile solutions are inoculated with dry soil. 



The author investigated air-dried soils which had been kept in 

 tightly stoppered bottles for from twenty-five to thirty-threa years, 

 and made experiments to determine (i) the number of organisms 

 present, (2) their physiological characters as manifested by their 

 ammonification, nitrification, and nitrogen fixation powers. The soils 



