&81 



THE DOGMA OF THE CONSTANCY OF SPECIES. 



A fundamental objection I make to some conclusions in Messrs. Baker and 

 Smith's work is that thev inculcate and insist upon the exploded dogma of the constancy 

 of characters in species. It is true that sometimes the authors endeavour to tone down 

 the word " constancy " be prefixing the word " comparative." 



In the '" History of Botany " by von Sachs. Oxford trans. 1890. chapter III is 

 devoted to *' Development of the Natural System under the influence of the Dogma of 

 the Constancy of Species." I take three brief extracts from the work :— 



"'. . . the idea of natural relationship on which the natural system exclusively rests, necessarily 

 remained a mystery to all who believed in the constancy of species ; no scientific meaning could be connected 

 with this mysterious conception; and yet the farther the enquiry into affinities -proceeded, the more 

 clearly were all the relations brought out, which connect together species, genera.'and families. Pyrame 

 de Candolle developed with great clearness a long series of such affinities as revealed to us by comparative 

 morphology, but how were these to be understood, so long as the dogma of the constancy of species severed 

 every real objective connection between two related organisms? . . ." (p. 110). 



'". . . The barren dogma of the constancy of species which, as Lange wittily remarks, comes 

 direct from Noah's ark . . ."*' ^p. 138). 



(Darwin) ".' . .is always pointing expressly to the fact that the natural system is the form in 

 which it has come to him, which he accepts in the main as the true one, is not built upon the physiological, 

 but upon the morphological value of organs . . . Like Robert Brown and De Candolle, he insists 

 upon the high importance for purposes of classification, of aborted and physiologically useless organs : he 

 points to cases in which very distant affinities are brought to light by numerous transition forms of inter- 

 mediate stages . . . " (p. 152). 



[The whole chapter should be carefully read.] 



Let us take a couple of passages out of Prof. F. 0. Bower's suggestive Hooker 

 Lecture, Journ. Linn. Soc., xliv, 110 (1917) : — 



'"'. . . In writing systematic works, the sole endeavour must be to arrange the material so as to 

 indicate phylesis. It seems easy at the present day to grant this in theory, but it is difficult indeed to 

 carry it out consistently in practice. For it involves the whole problem of Natural Relationships, which 

 should be based upon the sum of all knowledge relating to the organisms classified." (p. 110). 



" The outlook of the pre-Darwinian systematist must have been highly unsatisfactory to any 

 intelligent man. On the one hand he found the deeply-ingrained belief in the Constancy of Species. This 

 doctrine, introduced originally by Linnaeus as a summation of his experience, was for a century accepted 

 by his followers as an accepted truth. But, on the other hand, there was a growing sense of the kinship 

 of living organisms. ' Natural Affinity ' was instinctively recognised as a consequence of close com- 

 parison. The instinct translated itself into methods of grouping together such forms as have prominent 

 features in common into genera and families. Such relationship and consequent grouping was exem- 

 plified in all divisions of the Vegetable Kingdom. If this was merely a reflection of the plan of separate 

 Creation of Constant species, well might Elias Fries remark that there was ' quoddam supernaturale ' in 

 the Natural System.'" (p. 109). 



And in " Journal of Heredity " for April, 1919, we have — 



'' In spite of the epoch-making discoveries of Kolreuterer and Sprengel, biologists still believed in 

 the dogma of fixity of species. A new era was not opened until early in the 19th Century." (p. 152). 



Messrs. Baker and Smith's views as to the constancy or fixity of species are quite 

 clear. Mr. Baker has strongly held to the view of the Constancy of Species for very 



