4"t Pwrf. M < P.-tti-r. fi,i n ],, 



while the indiarublH-r cork wa- boiled f,,r half an hour in a 10 per 

 cent. >olution of contrive >ublimatc. The flask having c<Hled was 

 then about half-tilled with sterile l>Iock> of living turnip, prepared a> 

 de-"ibrd above, and inoculated with a pure culture of /'. <l>'<trn< ////>. 

 The indiarublier cork, after U-ing washed in sterile water, was quickly 

 in>erteil into the Mask, the glass tube l>eing pushed through the 

 perforations and the juiu-tions >ealed with melted wax. The longer 

 tuU- (A) i-eached to the liottoin of the flask, the shorter (B) only 

 slightly protru<led downwards through the eork. The action of the 

 bacterium could le detected in the course of twelve hours, the Mocks 

 changing colour and showing signs of disintegration at the edges. 

 During fermentation, a considerable quantity of gas was given off, 

 which could le collected from B over a pneumatic trough, the fluid 

 which soon accumulated at the liottoni of the flask rising in A, >upply- 

 ing the requisite pressure. When the' longer tulie A was left open, 

 and a sufficient supply of oxygen could diffuse into the flask, carbonic 

 acid was continually given off, and in the course of alout n week the 

 contents l>ecame entirely rotten and reduced to a watery mess. When, 

 however, in a precisely similar flask used as a control, the longer tul>e 

 after a short interval was closed, and the shorter connected with a 

 tube for collecting any gas given ott', thus cutting oft' the supply of 

 oxygen, the evolution of CO.. soon ceased, and, as far as could l>e 

 observed, the action of P. tkstntcfau ceased also. 



To carry this |>oint a step further, and to ascertain more definitely 

 whether the action of Ptmdomena* could take place in the absence of 

 oxygen, another series of flasks wa> fitted up with the two tules as 

 already descril>ed, the same precautions as to sterilisation* leing 

 adopt ei 1, and the prepared blocks of tin nip introduced and inoctila ted 

 as lefore. The shorter tiuV was now connected with a second flask 

 containing an alkaline solution of pyrogallic acid, and the other with a 

 l>ent tu1e containing mercury to act as a manometer, and prevent any 

 access of oxygen from the air. The first result noticed was an expul- 

 sion of the air in the flasks, the mercury rising in the distal limb. The 

 mercury continued to rise, bubbles of carlx>n dioxide eventually 

 ex-aping round the l>end. This action, however, cease* 1 in the course 

 of two day*, the available supply of oxygen in the flasks and inter- 

 cellular sjKices Injing exhausted. After a long interval (four months 

 .lune G to ()ctol>er 5) the flasks were disconnected, and the turnip 

 blocks examined. They still retained their original shape, and were 

 only rotten sujKjrficially ; the pieces had somewhat lost their rigidity, 

 but ottered considerable resistance when stretched. Microscopic 

 examination showed all the cells to be dead, but it was only one or 

 two layers of superficial cells which showed any evidence of bacterial 

 action. The cell-walls on the outside of the block were swollen and 

 striated, and could l>e readily separated along the middle lamella ; the 



