342 



of the reproductive organs; and it is siiggested that this may in many 

 cases prove an inii)ortant practical consideration, as in the case of 

 leguminous plants grown for fodder. * 



Some studies were made with reference to the morphology and nature 

 of the root tubercles of the pea. The form and character of the tila- 

 ments and hacteroids were carefully studied, and subsequently the 

 tubercles ]>roduced on the pea under the iiitlucnce of lupiuc extracts 

 were ol)served. In the latter case the tllaments were just as luimer- 

 ous and of the same geueral appearance as where the inoculation was 

 with bacteria from pea tubercles, and the bacteroids were of the form 

 found to be characteristic for the pea. This leads the authors to assert 

 that the formation of the tilaments and the general appearance of the 

 bacteroids is dependent, not upon the kind of bacteria causing them, 

 but upon the ])lant on which they are formed. This would seem to 

 sujiport Frank's th<*orv. that both tlie fihiinents and the bacteroids are 

 l)roducts of the cell [ilasin of the i)lant rather than of the bacteria them- 

 selves. However, forms believed to be bacteroids were found, often in 

 large numbers, in the jnue cnltnres and esjiecialiy in those of Injtine 

 bacteria. This leads the anthors to agree with i'ra/.mowski tliat the 

 bacteroids ] II oceed fnnii tlie bacteria themselves. They also express 

 the belief that the nitr(»gen w liich the jdant gets by this symbiosis is 

 very largely a jtrodnct of th«' nietalxdism of the bacteria, and that only 

 a relatively small jiortion is derived thi<tngh the absorption by the 

 l»lant of the bacteria or bacteroids. 



Vegetation experiments in boxes, F. Wohltmann and H. 

 Schefiler [Hry. mts <l. i>lii/si(>l. Lnhdrdtorimn u. >L VnsKrlisdnstaJt <J. 

 hiiidir. lust. )l. I'liir. Ilallc, 7 (lss7); ihitl, N {I'^Hl). — in the year ISS."), 

 Dr. Wohltmann began an extensive system of exi>eiinients in the 

 experimental gaidcn of the Agiicnltnial Institnte of the I'niversity 

 of llalh', the pnrpose ol which, as exi»resscd in the title of his 

 descrijitive memoir, was to fiirnisli "a contribntion to the testing and 

 ini]»ro\('inent <»!' the nicfhods of exact e\]teriment for the solution of 

 cnrrcnt qnestions regarding the treatment of soils and cultivation 

 of plants." rntain inii)r<»\«Mnents njion Wagni'r's method of pot expe- 

 riments as then develojied were attemjited by Wohltmann. and the 

 o](|tortnnity was utilized for stutlying the gi(»\vth of jdants under the 

 action of different fertilizers in a soil of a tyjic very common in north 

 (lermany. 



Wagner nscs zinc cylinders, which are ]»]accd npon small cars s(» as 

 to be con\ cniciitly liandlcd and iiin niider a co\ ci- when necessary for 

 protection from storm (»r frost. To these cylinders Wohltmann makes 

 scNcral objections, of which the chief are in snbstance that since they 

 are c\|>osc(l on all sides to air and the son's rays, the soil in them must 

 nnderg(» gieatcr changes in temperatnr«' than in its natural sitinition; 

 that the surface area is n(»t large emuigh ; that tin- dc]»th is not snflicient 

 for normal root d«'\ cUtpment : and that tlu' water supply and <liainage 

 are n(tt n(»rmal. To pro\ idc the desired surface area, deptii. and bulk 



