340 



experiment. The difference between the locality of the lupine and pea 

 bacteria is believed to be due to a less energetic action of the lujiine 

 bacteria, and this theory is borne out by the giowth of the i)lants in 

 general. In relocated trials the pure cultures from Eobinia soil or tuber- 

 cles failed to produce any effect upon the peas. The authors believe that 

 there can not l)e the slightest doubt that the pea and Robiiiia bacteria are 

 different in their physiological action, and that if they do not rei)rest*ut 

 different groups or varieties they at leastrepresentseparate modifications 

 with regard to the jnocess by which they derive their nourishment. 

 Differences were also noticed in the growth of the colonies and the 

 microscopical appearance of the bacteria from the two sources, the 

 colonies of Eobinia l)acteria being somewhat lighter-colored than those of 

 the pea bacteria, etc 



Lupine plants were treated with ammonium sul])hate or inoculated 

 with crude infusions of lui)ine soil (fresh samjile) and lal)urnum 

 tubercles, and with pure «ultures of bacteria from lu]>in«' tiibereles and 

 soil, pea tubercles, Gleditschia soil, liobinia tubercles and soil, and 

 laburnum tubercles. One vessel received no nitrogen or inoculation. 

 The growth of the plants was weak in all cases. Only those ])lauts which 

 were inoculated with bacteria fromlu]>ines ]»ro<luce<l root tubercles, this 

 result contirining in every way tlu' results previously obtained with 

 Koltiiiia and peas. The obser\ ation made in the case of K(»biiiia, that 

 the tubercles Avere without action w hen formed so late that the l«*aves 

 were no longer in a condition to assimilate and so re«'over from the 

 starvation period, was confirmed in the case of lujtine. 



The object of the trial with beans {PJhiscoIus i-uh/aria) was to test 

 the truth of the statement made by Frank,* that since the seeds thenj- 

 selves c()ntain bacteiia, beans are cajmble of forming tubercles, even 

 when grown in sterili/,«*d soil, without inoculation. The ])lants were 

 tieated with calcium nitrate or ino<ulated with bean soil infusion and 

 with ])nre cultures of ba«'teria from ]»ea, lupine, and liobjnia soils and 

 tubercles. Two cultures remained sterile. Only those plants which 

 were inoculated with bean soil infusion oiwitli jmre cultures of bacteria 

 from \n'ii s(»il or ]»ea tnbei'cles jirodiu'cd tuluMcles in any considerabh* 

 number. This plant, then, i>resents no excepticni among the papiliona- 

 «('ons i»lants with respect to the fornmtion of tubercles in sterilized soil. 

 It was observed that where tlie ]>lants were inoculated with bean soil 

 extract or with \)mv cultures of jtea tnl)ercle bacteria, the root tuber- 

 cles were on snuill roots of tin* third or<ler. In most cases a root of 

 the fourth order sprang from the tubercle, and this root often became 

 nuu'h stronger than the root of the third order which bore the tubercle. 

 It was also ibund that the roots sjninging from the tu])ercles were 

 remarkable for the amount of crystals of oxalate of lime which they 

 contained. The authors believe that the processes which lead to the 

 increase of nitn>gen in the plant take place in the tubercles, and that the 



Lamhv. Jabib., 19 (IH^). 



