( 398 ) 



corresponding to the stimulus 900 are ratlier too small, as well for 

 the height of twitch as for the heat-production. Calculating from the 

 observed lifting-height the corresponding magnitude of stimulus, we 

 find 810 instead of 900. Now taking this number 810, to calculate 

 the heat-production, we obtain 12, in perfect accordance with the 

 observation. The supposition that the number 900 is an error and 

 that 800 was meant is not very hazardous. 



From the communicated series we may draw firstly this conclusion 

 that the heat-production, considered as total effect, increases virtually 

 with increased magnitude of stimulus in the manner indicated l)v the 

 established formula. 



In the three last series Bw, the increment-constant for the thermal 

 effect, proved to be always smaller than the Bk corresponding to it, 

 a fact predicted alreadv in our deduction. We found for the number 



Bh 



n = ~- in series H, A and M tiie \alue 2.5, 4.23 and 2.31. Thouali 



of course even by this fact our deduction may not be deemed absolutely 

 proven, it nevertlieless affords a valualile support for considering the 

 deduction proposed by me as a most useful working-hypothesis. 



Bacteriology. — "On a colourless bacterium, whose carbon food 

 comes from the atmosphere.'" By Prof. M. W. Beijerinck 

 and A. van Delden. 



We give tlie name of Bneilhi.-< oli]/ocnrhophiIus ^) to a colourless 

 bacterium, whose carbon nutrition in the dark (and likewise in the 

 light), takes place at the expense of a not yet well-known atmospheric 



1) It is probable that W. Heraeus (Ueber das Verhalten der Bacteriën in 

 Brunnenwasser sowie über reducirende imd oxydirende Eigenschaften der Bacteriën. 

 Zeitschrift f. Hygiene, Bd. I, pag. 226) already in 1886, has bad cultures 

 of B. oUgocarbophilus before him. He says the following : .... „Ausser- 

 ordentlich auffallend war das Erge'miss dieser Yersuche in der Hinsicht, dass eine 

 Vermehrung der Bacteriën in einer Fliissigkeit eingetreten ^Yar, welche keine 

 organische Verbindungen sondern nur Salze enthielt. Ein unansehnliches, kaum 

 sichtbares Piinktchen von Bacterienzoogloeën batte sicb im Verlaufe vom zehn Tagen 

 so stark vermehrt, dass die ganze Oberfliicbe der Lösung vor. einer dicken Haut 

 bedeckt war." Analytical results are not given, and the remark makes the 

 impression of being accidental and is lost among insignificant observations. — 

 Winogradsky's statement, concerning the accumulation of organic carbon in nitri- 

 fying solutions, evidently refers likewise to this microbe, but his description suffers 

 of indistinctness (Annales de I'lnstitut Pasteur, T. 4 pg. 270 et 462, 1891).— In the 

 experiments of Godleswki (Bulletin international de 1' Académie d. sc. d. Gracovie, 

 Dec. 1892 pag. 408 et Juin 1895 pag. 178), the vanished CO^ is not, as he thinks, 

 absorbed by the ferments of nitrification but by the Mg . Mg GG'^. 



