I is prof. M. C. Potter. 0,i " Bacterial 



lively slow development. In sections from more succulent 



roots the walls have been found to swell from 2 p. to 7 /* in the course 



of twenty-four hours.) In fig. 4 the cell is drawn from a section im 



Fig. 4. Secli >n immersed in solution of cvtase for forty-two hours, whose power 

 had been destroyed by boiling. Cell-walls quite normal (Zeiss, E. oc 2). 



mersed for forty hours in the boiled liquid. The cell-wall is not per- 

 ceptibly thickened or affected in any way. 



The activity of the enzyme in the decaying plant was also shown 

 by passing the juice from the bruised pulp directly through a Pasteur- 

 Chamberland filter, when its action on the cell-wall was precisely that 

 described in the case of the watery extract of the alcoholic precipitate. 



The bacterium also secretes the enzyme when growing in a leef 

 solution. Small flasks containing 100 c.c. of beef bouillon, inoculated 

 with a pure culture, became turbid in the course of twenty-four to 

 thirty-six hours. After an interval of eight days, the liquid was 

 filtered and diluted with five times its bulk of alcohol, when a 

 precipitate immediately began to appear. After standing twelve 

 hours the precipitate was collected by filtration, dried, and then 

 digested with 10 c.c. of distilled water. After filtration through a 

 Pasteur-Chamberland filter, experiments were repeated as above with 

 sections of sterile turnip, and the same results were obtained ; tin- 

 liquid was found to possess the property of dissolving the middle 

 lamella, and causing the softening and swelling of the cell-wall. All 

 action of the ferment was destroyed by boiling. 



To avoid the tedious process of the filtration through a Pastcur- 

 C-hamberland filter, and the necessary sterilisation of the apparatus, 

 various attempts were made to render the solutions aseptic by the use 

 of such re-agents as chloroform, thymol, formalin, &c. But this process 

 had to be abandoned, as in all these cases living bacteria were found 

 -after twenty-four hours, and no reliance could be placed upon it. 



In the early stages of the investigations, filtration except when 



