232 BACTERIOLOGY. 



sufficient are necessary for completeness) in 

 order to represent everything that the prefix 

 Ur denotes to a German. It is the absolute 

 thing " that exists behind all change and 

 remains primordially the same" as Helmholtz 

 expressed it. This alone we now call cause, 

 Ursache, both in the exact sciences and in 

 epistemology, and we accept nothing but that 

 conception as true and sufficient. Only what 

 is provided for in the cause both in quality 

 and quantity can appear as effect, and every- 

 thing that appears as effect already exists in 

 quality and quantity in the cause, that is, in 

 the internal organization. 



Resistances and External Conditions. 



In a strict sense causes may pass over of 

 themselves, freely and spontaneously, into 

 their effect, as when a thrown or lifted weight 

 immediately falls. In practice, as a rule, this 

 does not happen, since in order to render a 

 definite work possible, we prevent the raised 

 weight from immediately falling again by 

 hanging it up by a cord or by placing a sup- 

 port under it. Such a resistance to the im- 

 mediate conversion of potential energy into 

 work may be removed in a given case easily 

 or with difficulty, and a corresponding appli- 



