THE FACTORS OF HEREDITY. 95 



"The tendency is to produce an exact copy of 

 parents in offspring." This law is modified by a 

 secondary law, namely, that the acquired char- 

 acters of one generation are transmitted to the 

 next.* In a sense these two laws stand in direct 

 opposition to each other. The former is the con- 

 servative, while the latter is the radical principle 

 in transmission. Through the operation of the 

 primary law the fixed characters of the species are 

 reproduced and their established peculiarities 

 maintained. Through the operation of the second- Tfae Opposing 

 ary law the acquired characters of each genera- Principles of 

 tion are transmitted to the next and become a 

 part of its hereditary nature* If the first were the 

 only law of heredity, then the species must for- 



*The doctrine of the transmission of acquired characters 

 as taught by Darwin, Lamark, Spencer, Dugdale, Lombroso 

 and others has been strongly opposed by Weismann and 

 those who have accepted his theory of "germ plasm." A 

 reaction, however, has already taken place among biologists 

 so that Weismann's theory, as originally set forth, has com- 

 paratively few supporters, while his own revised statements 

 bring his theory not far from those of Darwin and Spencer. 

 Certain it is that all close observers of human nature, not 

 biased by an opposing theory, accept the "doctrine of the 

 transmission of acquired characters. Of this fact I shall 

 have more to say later. 



*The terms "fixed characters" and "acquired characters" 

 must be considered as only relative terms. There are in 

 reality no "fixed characters" in nature. Constant cha'nge is 

 the law of the universe. All so-called "fixed characters" 

 have been acquired, but what has been long acquired and 

 so often repeated as to have become an established factor 

 in the physical or mental constitution of a species is called 

 a "fixed character" in counter-distinction to those recently 

 acquired. 



