( 828 ) 



In the dark, also, absorption of methan was with certainty observed. 



However, the hij)se of time preceding tlie first perceptibility of 

 the process in dilferent experiments with the same species of plant, 

 varied very ninch, bnt when once set in it went on rapidly. When it 

 was moreover observed, that by carefnlly washing the plants the setting 

 in of the absorption was mncli slackened, whilst it seemed probable 

 that jnst then an acceleration would follow in case the plant itself 

 absorbed the methan, and especially when furthermore the absorption 

 was observed to take place only after a slimy film had covered the 

 water in the flask, it became evident tliat the oxidation was not 

 caused by the green plant itself, but by microbes living on it surface. 



In order to study the process more exactly an apparatus was 

 constructed allowing us to pursue the absorption as well qualitatively 

 as quantitatively. 



It consists, as siiown in the figure, of two EkLENMEYER-flasks of 

 i: 300 cc, each closed by an indiarnbber stopper with two perfo- 

 rations and joined by a twice curved glass tube reaching to the 

 bottom of the flasks, Avhich bears in tlie michlle a glass cock. The 

 flask, destined for the cultivation of tlie bacteria, bears, in the second 

 perforation of the stopper, a tube with a glass cock to admit the 

 gasmixture; the other flask is fitted with a glass tube filled with 

 cotton wool. 



The use of this apparatus is as follows: For tlie crude culture 

 the first mentioned fiask is quite filled with the culture liquid : 



