46 BACTERIOLOGY 



those of the enzymes of the non-disease producing group, 

 while in others this is not the case. In the case of certain 

 pathogens, as with the yeasts and certain saprophytic bacteria, 

 these toxins poisons are so bound up with the protoplasmic 

 bodies of the bacteria that they become effective as poisons 

 only on the disintegration of the cells containing them; these 

 are the "endotoxins." In other instances the poisons are 

 diffused through the surrounding medium in which the 

 bacteria are growing and may readily be separated from 

 the cells forming them by the simple process of filtration. 

 These are the free or "true toxins." 



At one time there was believed to be an essential difference 

 between the "organized" and "unorganized" ferments, but 

 when in 1897 E. Buchner expressed the active ferment from 

 the yeast cell, and demonstrated that this active principle, 

 "zymase," without the aid of the living cell, is capable of 

 transforming sugar into aclohol, just as is done by the 

 intact living yeast cells, it became manifest that the old 

 distinction between "organized" and "unorganized" fer- 

 ments is after all not important. The "enzyme" is the 

 active agent and in so far as the result is concerned it matters 

 not if it be tied up in the body of a cell or diffused freely in 

 the medium surrounding the cell. 



The same may be said with regard to the analogous 

 "endotoxins" and "toxins" elaborated by the pathogenic 

 species, though it must not be assumed that the toxins act 

 in the same way as do the ferments or enzymes. Such 

 knowledge as we have of the mechanism of certain toxic 

 activities justifies the statement that the poisons of some 

 pathogenic bacteria enter into a destructive combination 

 with body cells for which they have a specific affinity and 

 that there and then their activity ceases; the result being 



