46 BACTERIOLOGY. 



be found in bacteria and the " infusion ani- 

 mals " ought, in my opinion, to have weighed 

 against the doctrine of " spontaneous gener- 

 ation." We are now no longer able to accept 

 Ehrenberg's conception of the structure of bac- 

 teria, yet the knowledge we do possess is 

 sufficient to discredit the notion that bacteria 

 can arise by spontaneous generation. The 

 bacterial cell is much too complicated and 

 too far removed from the ideal " simplest 

 cell " to admit of this view. The experi- 

 ments devised to support the belief in their 

 spontaneous development out of inorganic 

 or altogether lifeless material have moreover 

 always miscarried. The one undeniable fact 

 in the matter is that certain granular proto- 

 plasmic elements can outlast the life of the cell. 

 In this latter category belong especially 

 those effects due to the so-called lifeless fer- 

 ments or enzymes. The digestive ferments 

 of the higher animals are in the first instance 

 nothing but extruded cell-protoplasm and often 

 appear like a sort of cell-slime. Among bac- 

 teria also such ferments occur independently 

 of the life of the cell. Fermentative manifesta- 

 tions, however, constitute only a limited part 

 of the vital phenomena of the cell. The 

 formation of enzymes, outlasting the cell and 

 indeed to a certain degree independent of it, is 



