THE HISTORY OF BACTERIOLOGY. 445 



the doctrine of microzymes, that is of the 

 origination of active granules in the living 

 organism ; in the hands of Wigand it became 

 the doctrine of the anamorphosis of protoplasm, 

 that is, of the transformation of higher cell 

 protoplasm into bacterial protoplasm ; and in 

 those of Fokker, the similarly conceived 

 doctrine of heterogenesis. The kernel of 

 truth in the whole matter is that there really 

 are cellular elements whose activity lasts 

 longer than the life of the cell. All the effects 

 of this sort are in the same class with the 

 power manifested by the " active " proteid se- 

 creted by the gland-cells in the form of the 

 solvent enzymes ; these enzymes often appear 

 as cell granules which have outlived the cell 

 and have become independent, but they only 

 display part of the cell activities, and are not 

 capable of forming new cells. 



If the " infusion animals," and in this 

 group were included the organisms we to-day 

 call bacteria, could not arise in albuminous 

 fluids by spontaneous generation, but could 

 spring only from germs of their own kind 

 which had somehow made their way into the 

 fluids, then on the other hand it must be as- 

 sumed that the germs in proportion as they 

 multiplied would evoke various decompositions 

 by virtue of their life activities. This was 



