BOTANY. 381 



In the cuttings of Saliv the effect u]>on tlie shoots of removing the 

 roots and vice versa made itself apparent rehitively early. The first 

 thing to be ]ioticed was a diminution in the develo])ment of the roots 

 of those cuttings whose shoots had been removed, and somewhat later 

 the development of the shoots whose roots had been removed. By 

 analogy with the seedlings the opposite result would havb been antici- 

 pated, as iu the seedlings the roots asserted their independence of the 

 shoots the longer. 



It remains to determine- by a more extended investigation to what 

 extent the principles of correlation, as manifested m the growth of 

 these few species, are of general application. 



Are .non-leguminous plants able to assimilate free nitrogen? 

 F. XoBBE and L. Hiltner {Landw. Ver.s. Stat, 45 {lt>94), ]S!o. 1 and 5, 

 pp. 155-J'j9). — The ability to assimihxte the free- nitrogen of the air as 

 possessed by tubercle-forming plants, such as legumes, alders, Mea/jnus, 

 Podoe<irp}iH, etc., is recognized, and the claim recently set forth that 

 non-leguminous or non-tubercle-forming plants have the same jiower 

 was investigated by the authors. Iu those jdants able to assimilate 

 free nitrogen an increased nitrogen content is shown in their leaves 

 and other parts above groniid. It is claimed that some non leguminous 

 plants, as mustard, are able, indirectly, to contribute to the enrichment 

 of the soil by stimulating to greater activity the known soil organisms. 



In 1893 a series of experiments was conducted with mustard plants 

 growing in sand, to which varying amounts of uitrogen were added 

 from time to time. The total yield of nitrogen kept pace with the 

 varying amount of soil nitrogen, and there was no increase due to 

 assimilation of free nitrogen. 



On June 15, 1893, a series of exi)eriments with peas, mustard, buck- 

 wheat, and oats was begun. Nine pots of 5 liters capacity were filled 

 from a mixture of 4,329 gm. sand and 1,000 gin. garden soil. The soil 

 contained an average of 0.332 per cent of nitrogen, or 3.320 gm. per 

 pot, 0.447 gm. being soluble. In addition each pot received 0.5 gm. 

 l)otassium chlorid and 5 gm. calcium phosphate. The mixture of soil 

 and sand was sterilized and then inoculated with an extract from a 

 mixture of soil in which all 4 plants had previously grown. Two 

 pots each were jilanted with 10 seeds of peas, mustard, buckwheat,. and 

 oats, and 1 pot left as a check. The aerial parts of the plants were 

 harvested July 15, when the mustard and buckwheat were just coming 

 into bloom, and tahular information is given as to the height of the 

 plants, their dry matteij and nitrogen content. On July 27 and Sep- 

 tember 8 a second and third seeding were made as before, and the 

 plants were harvested September and November 7. Tabular informa- 



