BOTANY. 967 



Tlie iinthor isolated the bacteria from soils on which wheat and clover 

 liad been grown, and also from compost, making numerous pure cultures 

 of them. Pot experiments were made to test their influence upon the 

 growth of oats. The pots used were 22 cm. in diameter and each 

 received 40 cc. of a bouillon culture, and all received the same fertilizers 

 and treatment. At maturity the plants grown in the pots receiving the 

 bacterial cultures gave as an average 18.46 gm. grain and 29.9 gm. straw, 

 as compared with 13.26 and 22.14 gm. from the check pots. 



Additional experiments were made to test the comparative value of 

 the different kinds of bacteria isolated, the highest yield being secured 

 when Bacillus 39 was used for inoculating the soil. 



In 1893 some field experiments were undertaken with oats in which 

 the seed, prior to sowing, was impregnated with the desired organism 

 by soaking for some time in liquid cultures containing it. The yields 

 of grain from uninoculated seed and from seed so treated were in the 

 proportion of 100:135. In the autumn the field where the oats had 

 grown was plowed and in the spring sown with mustard. The yields of 

 green forage on equal portions of uninoculated and inoculated plats 

 may be represented by the proportion 100: 195. 



Numerous additional exi^eriments were conducted which in every case 

 gave a higher total yield whenever the soil or culture medium had 

 received an inoculation with some form of soil bacteria. 



The author made no attempt to show how the bacterial inoculations 

 influenced the greater growth and productiveness of plants growing in 

 inoculated soil, but he thinks it probable that the isolated bacteria used 

 in the cultures possessed the same power of assimilating free nitrogen 

 that is claimed for ordinary soil bacteria. 



Upon some properties of soils which have grown a cereal 

 crop and a leguminous crop for many years in succession, J. B. 

 Lawes {Agl. Students' Gaz., 7 (1895), JSfo. 3, pp. 65-92, pi. 1). — On a part 

 of a field which had grown wheat for 39 years the crop was not cut in 

 1883, but all the grain was allowed to fall and thus reseed the land. 

 No weeds w^ere removed. In the second and third years there were 

 only a few wheat plants, some of them having slender stalks and only 

 .one or two small seeds in the ear. 



Four years after this field passed out of cultivation there were found 

 growing in it 40 species of plants, and after 8 years more there were 

 51 species. Leguminous plants, especially Lathy rus pratensis, spread 

 and grew luxuriantly. 



In striking contrast with this was the paucity of species on an uncul- 

 tivated field, which, when in cultivation, had been devoted to the con- 

 tinuous culture of beans ; when the bean crop failed red clover and 

 barley had been grown for a few years, the clover affording large 

 yields. The vegetation on this field, when uncultivated, consisted of 

 a few tall tufted-growing grasses ; white clover growing in a pasture did 

 not cross the border into this field which had borne leguminous crops 

 for so long. For the cause of the luxuriance and variety of vegetation 



