BOTANY. 



469 



Some recent investigations concerning soil inoculation -with 

 pure cultures of tubercle bacilli for culture of legumes, F. ^sObbe 

 {Chcm. /J(j.. 20 {ISDO), No. so, pp. 7S5, 780). — The followiug- is au 

 abstract of a paper presented by the author before the botanical sec- 

 tion of the AssociatioQ of German Naturalists and Physicians at the 

 Frankfort meeting, September, 1896. 



Experiments ^vith sand and water cultures of various legumes and 

 other plants were reported in which it was shown that legnmes, Eleag- 

 nus, and possiblj' FodocarpuH aiKjuNtatus are able to fix free nitrogen 

 through symbiosis with bacteria and not through their leaves. Mus- 

 tard, oats, and buckwheat are said to be unable to assimilate free 

 atmosi)heric nitrogen. 



The relation of the various bacteria to one another and the effect of 

 any specific bacteria upon a different host plant was shown, the latter 

 phase having been recently given in much greater detail (see above). 



Concerning the effect of inoculation upon nitrogen containing soils, 

 it was shown that tubercle bacteria are rather sensitive toward certain 

 chemicals. The formation of root tubercles was greatly retarded by 

 the presence of potassium nitrate, while ammonium sulphate was with- 

 out injurious effect. The following table shows the effect on hairy 

 vetch of adding nitrate of potash to inoculated pots : 



Yield of hairy vetch u-itli atid tvithoid jjotassium nitrate. 



The duration of efflciency of tubercle bacteria when cultivated upon 

 gelatin was examined. It was found that in practice the vitality of 

 the bacteria is not impaired within 2 or 3 months if the culture is kept 

 from strong light. Cultures 7 months old were found to be worthless. 



Concerning the after effect of inoculation upon crops, pots were inoc- 

 ulated with pea, robinia, and red clover bacteria, and the following 

 year seeded with peas, robinia, and red clover. The dry matter of the 

 harvested material was as follows: 



Yield of (Ivy matter from poln inoculated previous year. 



Peas 



Kobinia .. 

 Ked clover 



Inoculated with bikcteria 

 of- 



Bed 

 clover. 



Gm. 

 9.3 

 2.2 

 14.4 



