290 CONCLUSION 



The close inter-relations and interchangeability that I have 

 shown to exist between the varied lower types of life with which 

 we have been concerned actually force upon us the belief, that 

 the forms assumed are as much the immediate results of their 

 molecular composition and their environing forces as are the 

 various forms assumed by crystals. We are driven to the belief, 

 in fact, that 'organic polarity' is the dominating influence in the 

 production of this or that form belonging to the great assemblage 

 of ' Ephemeromorphs ' ; that heredity in any other sense is not 

 operative among them ; and that this whole world of lowest 

 vegetal and animal forms of life must be wholly removed from 

 the influence of Natural Selection. 



I am well aware that these are very unorthodox views— that 

 Darwin, Weismann, Poulton and others actually believe that the 

 rate of change is lower among lowest than among higher organisms. 

 This most surprising view is based, in the main, upon the fact dwelt 

 upon by Huxley and others as to the "persistence of types" 

 through geologic ages — a fact which, with the proof of the occur- 

 rence of heterogenesis, is, as we shall see, capable of receiving a 

 totally different interpretation, and one in no way inconsistent with 

 the recognition of all that has been shown by multitudes of workers 

 as to the extreme variability of these Ephemeromorphs, and the 

 pleomorphism of such organisms as Protococcus, Hcematococcus, 

 Chlamydomonas, Sphaeroplia and others. The changes among these 

 latter organisms are indeed so fitful, and vary so much in their order 

 at different times and seasons (as witness different observers) that 

 many of their varying changes could scarcely be considered to 

 be results of heredity. Like actual heterogenetic transformations, 

 such irregular variations must be considered to depend upon slight 

 isomeric changes in the molecular constitution of their 'physio- 

 logical units,' acting in conjunction with organic polarity as a 

 formative principle. 



The extreme variability of the organisms referred to above is 

 well illustrated by the researches of Prof. F. Cohn on Protococcus 

 ■pluvialis ; and such observations by an investigator of great repute 

 may be cited as an example of many others.' He discovered, as 

 derivatives of this apparently simple Alga, the most widely differing 



" See Transln. of his memoir, with Plate, in " Botanical and Physiological 

 Memoirs," Ray Soc. 1853. The reader may also consult Cook's " British Fresh 

 Water Algse," for details as to the great variability of the other forms mentioned 

 above. 



