150 Causes and Course of Organic Evolution 



a real advance exists along each family, as was beautifully 

 shown by Huxley for the genus Gentiana (67: 101). Such 

 advance in floral color nearly always is correlated with ad- 

 vancing morphological specialization of the flower as a whole. 

 We need only cite such families as Liliacese, Iridacese, Orchid- 

 acese, Ranunculacese, Papaveracese, Caryophyllacese, Mal- 

 vaceae, Rosacese, Fabacese (Leguminosse), Myrtacese, Aster- 

 acese, Campanulacese, most families of the Bicarpellatae in 

 the widest sense, amongst many others that could be given. 



Now the question arises: are such appearances and disap- 

 pearances, or are such frequent appearances at different stages 

 of the evolutionary process, to be explained by our supposing 

 that certain substances are evolved as totally new and "ac- 

 quired characters" at certain points along the main lines and 

 the by-paths of the great evolutionary road, to be again lost 

 in some cases, or to be replaced in other cases by different 

 but related substances? Or is there not rather a large series 

 of bodies common to all plants, and specially to the Caryota, 

 which can at any time be gradually reproduced by the joint 

 action on, and reaction of, protoplasm and its related ferments, 

 under the more fundamental action of appropriate environ- 

 mental stimuli.? For, further, as -wall be accepted later, if 

 such stimuli change in quantity or quality, so might the repro- 

 duced bodies change, even to the extent of seeming to be again 

 absorbed, or possibly represented by ultra-microscopic particles. 



The latter of the two above alternate views is that which 

 the writer in his lectures has advocated during the past four- 

 teen years, as being the one which is abundantly and ^-idely 

 supported by observations and experiments, some of which ^dll 

 be presented in a later chapter. 



If such be the condition of affairs, varietal, specific, generic, 

 and wider characters resolve themselves into the waxing or 

 waning of definite substances, according as environal stimuli 

 act on certain constituents of the cells. It follows also that 

 most of the discussion on the possible acquisition of new char- 

 acters, on the hereditary transmission of such, on dormant 

 and recessive factors, have mainly been of value in stimulating 



