152 BACTEKIOLOGICAL AND ENZYME CHEMISTRY 



depended in this case on the organism. With different con- 

 ditions of experiment different results are obtained, and the 

 production of a dextro or Isevo form depends quite as much 

 on the fermenting medium as on the organism producing the 

 fermentation. The dependence of the products of the reaction 

 upon the constitution of the fermenting molecule has been the 

 subject of a very interesting research by Harden, who has 



24. — ^Appabatus used in De. Habden's Expemmbnts on 

 B. coli communis. 



studied the chemical action of B. coli communis and similar 

 organisms on carbohydrates and allied compounds. 



The apparatus shown in Fig. 24 was made use of ; one litre 

 of the solution was placed in a large flask provided with a 

 side tube and an indiarubber stopper, through which passed a 

 straight glass tube leading to the bottom of the flask, the side 

 tube and vertical tube were plugged with cotton wool and the 

 flask then steriKsed. The side tube was then attached to a 

 piece of bent tubing (A) on which a small bulb was blown near 

 the bend, a drop of mercury was placed in the tube and served 



