May, 1922 common misconxeptions of evolution 181 



criminating biologists may not be entirely free from this notion, 

 for I recall a little verse which used to be sung at Woods Hole, 

 that Mecca of the biologist, which runs as follows: 



"Once I w^as a Rhizopod, a protoplasmic cell, 

 I had a little nucleus and oh! I loved it well, 

 Now I am a man at last, by evolution's power, 

 But oh, my little nucleus! I need thee every hour." 



Evolution is merely an explanation of the way things have 

 come to be as they are, together with a statement of the natural 

 laws under which this has taken place. It involves uniformity 

 and continuity in nature and it applies to everything which has 

 undergone change in the course of time. 



Some of the confusion in the minds of those untrained in the 

 methods of science is undoubtedly due to the lack of a clear 

 understanding of what is meant by "natural law." A natural 

 law is merely a formula indicating a method of procedure in 

 nature. It is a statement based on the classification of facts and 

 the comparison of their relationships. Civil law, as a man-made 

 rule of conduct implies a restriction and compels conformity, 

 and changes continuously with the varying conditions of human 

 society. Natural laws are merely conclusions drawn from the 

 scientific study of organized series of facts and are immutable 

 except as they are modified by a re-classification and re-state- 

 ment. A careful reading of the third chapter of Karl Pearson's 

 "Grammar of Science" is recommended to all interested in 

 this matter. "The civil law involves a command and a duty; 

 the scientific law is a description, not a prescription. The civil 

 law is valid only for a special community at a special time ; the 

 scientific law is valid for all normal human beings, and is un- 

 changeable so long as their perceptive faculties remain at the 

 same stage of development." 



Another misconception of evolution is involved in the idea 

 that it always means an advance of some sort toward higher 

 organization. This idea is contrary to the very method of 

 evolutionary processes. Variations may occur in any direction 

 in any group of organisms, as far as we know, and, theoretically, 

 at least, they are just as likely to be retrogressive as progressive. 

 Secondary simplification is very commonly observed, especially 

 in parasitic organisms. 



