560 PROTOCOCCUS PLUVIAL1S. 



A critical and comparative consideration of the fore- 

 going facts would therefore appear to render untenable 

 almost all the principles which modern systematists 

 have hitherto adopted as the basis for the construction 

 of their Natural Kingdoms, Families, Genera, and 

 Species. 



But it must not hence be concluded, that the result 

 of these investigations implies the existence of a state of 

 complete anarchy in the domain of microscopic organisms ; 

 or that any one form among them, may assume any 

 other form indifferently; that, in fact, there are no real 

 species in the invisible world. Such is by no means 

 the case. 



Critical enquiries such as the present, have for their 

 result like the spear of Telephus the healing of the 

 wound they inflict. It is manifestly better, although at 

 the expense of erroneous notions, long admitted as in- 

 fallible to substitute, by the aid of a complete and 

 continuous history of development, a much more defined, 

 because natural idea, of Genus and Species, for that 

 hitherto set up, in artificial, but, at the same time, un- 

 natural Systems. 



