No. 580] 



ORIGIN OF SINGLE C 11 All At TF.Ks 



235 



ical, because in the production of these modern races 

 the pure ancestral forms had in their natural state 

 evolved a very large number of allometrons as well as 

 rectigradations and other numerical characters which 

 have to a slight degree blended in intercourse and to 

 a larger degree have maintained their purity and dis- 

 tinctness. Thus you will observe among the modern 

 races of horses the most incongruous mixtures; an old 

 cart horse with the head and quarters of the Forest 

 type will gallop across a field and raise the bones of the 

 tail perfectly erect exactly like a pure bred Arab. 



Similarly a 44 species" is a mosaic of an infinite num- 

 ber of least characters in a state of movement only a few 

 of which may be so definite and measurable as to be 

 employed in systematic definition. 



12. Theoretical Conclusions as to "Characters" and 

 the "Organism" 



These least characters when assembled in an organism 

 and dominated by the principles of separability and cor- 

 relation present to our fancy the picture of a vast regi- 

 ment of soldiers walking in single line ; each soldier pos- 

 sesses his own individuality and separableness from his 

 comrades, each advances or lags behind according to his 

 individual velocity, but each subserves the general pur- 

 poses of the entire regimental line through the uniting 

 force of training and the unseen spirit of the regiment, 

 which represents the law of correlation. 



It appears that we paleontologists have already learned 

 much and that we have still far more to learn by the clos- 

 est observation of "characters" in a state of natural evo- 

 lution. We are on somewhat safer ground than the ob- 

 server of the unnatural or hotbed evolution of characters 

 in the artificial breeds, hybrids of animals and plants 

 under domestication. The contrast between the excess- 

 ively slow natural evolution during the past million years 

 of the wolf, the arctic fox and the red fox, and the feverish 

 unnatural evolution of the domestic breeds of dogs dur- 



