TRANSMISSION OF MODIFICATIONS 355 



The writer does not propose to enter the disputed territory 

 at this point, for the reason that he does not believe in accept- 

 ing for these purposes the fundamental distinction between 

 " congenital " and " acquired " characters. The use of the term 

 "congenital" as distinct from ''acquired" is most unfortunate. 

 Any character present at birth is, by definition, congenital. The 

 list would include not only the characters typical of the race but 

 also malformations and deformities due to conditions in utero or 

 to unknown causes. Thus men have been born without feet, yet 

 the chances of transmitting the deformity are extremely remote. 

 An arm or a leg may be misplaced during embryonic develop- 

 ment and malformations result without essentially bearing upon 

 Khe conditions that are supposed to control inheritance. 

 Manifestly the most profitable distinction to observe regard- 

 ng the inheritance of variations is a strict discrimination be- 

 ween those that have arisen through causes affecting the germ 

 plasm directly, on the one hand (blastogenic), and those that 

 affect the body during its development, upon the other (somato- 

 genic). Now an accident to the embryo in utero is as much 

 external to the germ plasm the inherited substance on which 

 development depends as is an accident after birth, and there- 

 fore distinctions between congenital and acquired characters are 

 extremely misleading, especially among mammals ; less so, of 

 course, among birds, in which no such thing as birth exists. 



his Darwin and After Darwin. Cope, in his Primary Factors of Organic Evolution, 

 may be read with profit, as may Eimer in Organic Evolution. 



Both factions claim to be disciples and exponents of Darwin, but the opponents 

 of transmission, from their extreme appeal to selection, have come to be known as 

 neo-Darwinians, and the advocates of transmission have accepted the name of 

 neo-Lamarckians, from their belief in the formative influence of the environment, 

 which was the distinguishing feature of Lamarck's view of evolution. 



In general it may be said that, while there are many notable exceptions, the 

 zoologists tend to side with the neo-Darwinians against the idea of transmission, 

 while the botanists, dealing with fixed and of necessity much more plastic forms, 

 tend to go with the neo-Lamarckians. 



In the opinion of the writer, Lloyd Morgan is by far the most satisfactory 

 investigator and writer on this vexed question, especially in his Habit and 

 Instinct, which should be read by every careful student of this subject. The 

 inquiry is conducted to find out the truth, not to prove or to disprove the 

 inheritance of acquired characters, and his conclusions as stated on pages 307-322 

 of that volume may well engage the attention of the thoughtful reader, whatever 

 his personal views on the points in dispute. 



