January 7, 1898.] 



SCIENCE. 



17 



lished by N". H. J. Miller, in the Journal of 

 the Royal Agricultural Society of England, 

 Vol. 7, third series, part 2, pp. 236 et seq. 



The method employed by Dr. Salfeldwas 

 to spread upon the peaty soils large quanti- 

 ties of soils in which peas, beans and other 

 leguminous crops had been grown. Im- 

 mense quantities of the soil to be used to 

 develop the fertilizing ferments were re- 

 quired ; quantities ranging from 16 to 32 

 hundred weight per acre were used, and it 

 was found that the larger quantities gave 

 the better results. 



The particular bacterium which is most 

 active in developing nodules on plants has 

 been called the Bacillus radicicola. It was 

 found in Dr. Salfeld's experiments that 

 there exist many peaty soils which are bo 

 poor in this bacterium as to require inocu- 

 lation with other soils containing it before 

 leguminous crops can be grown success- 

 fully. 



As was to be expected, the most striking 

 results were obtained with soils which were 

 most deficient in the nitrifying bacillus, and 

 when the inoculatiou was accompanied 

 with the addition of a suflBcient quantity of 

 lime, phosphoric acid and potash. The 

 large quantities of soil which are re- 

 quired for the direct inoculation, as outlined 

 above, have rendered of great interest the 

 attempts to secure inoculation in a more 

 direct and positive manner. This has led 

 to a study of the possibilities of securing 

 pure cultures of nitrifying organisms which 

 can be applied directly to the seed before 

 planting, or can be mixed with moderate 

 quantities of soil and thus distributed over 

 a large area. 



The most extensive experiments in the 

 processes of seed inoculation have been car- 

 ried on by Professor Nobbe, of Tharand, 

 Saxony. The principle of these inocula- 

 tions is first to secure the pure cultures of 

 the bacteria inhabiting the nodules of the 

 roots. These pure cultures are obtained by 



the ordinary bacteriological processes now 

 so well known. With these pure cultures 

 inoculations of various kinds have been 

 practiced, viz., inoculations of the soil 

 itself, inoculations of the exterior of the 

 seed, and inoculation by pricking the seed 

 with needles bearing the germs of the pure 

 cultures. 



The remarkable fact has been developed 

 that while the bacteria derived from the 

 pure cultures of the root nodules of various 

 legumes appear to be microscopically iden- 

 tical they, nevertheless, have very dis- 

 tinct characters. The results of these ex- 

 periments have shown that in inoculation 

 best results are obtained when plants of 

 the same species and, as nearly as possible, 

 the same family are used. Even among the 

 LeguminosEe, when passed from one species 

 to another, the vitality of the organism is 

 either diminished or entirely destroyed. 

 This is illustrated, for instance, in attempts 

 which have been made to inoculate the 

 members of the pea family with the bacteria 

 taken from the roots of clover, or vice 

 versa. The commercial outcome of these 

 experiments is that these cultures have 

 been prepared on a large scale for general 

 sale. While the idea of thus preparing fer- 

 tilizers in a practically infinitesimal quantity 

 for field work is not a new one, and is not 

 lacking in its appeals to the imagination, it 

 cannot be said that the practical results 

 have been fully equal to the expectations 

 which have been aroused. 



The commercial name of these prepara- 

 tions is nitragin, although, etymologically, 

 probably the term nitrogene would have 

 been preferable, but it was necessary to dis- 

 tinguish it in some way from the name of 

 the element. 



The Imperial Seed Control Station at 

 Vienna made experiments with 100 kilo- 

 grams of soil taken from a field where lu- 

 pines had been grown, and 20 kilograms of 

 analogous soil coming from a field where 



