2IO A STUDY IN HEREDITY 



APPENDIX D 



CHARACTERS, CONGENITAL AND ACQUIRED 

 (Reprinted from Science, 17TH and 24TH December 1897) 



The characters of a living organism, plant or animal, are usually 

 grouped by biologists under two heads, the congenital or the 

 inborn, and the acquired. But, hitherto, no systematic attempt 

 has been made to give precision to these terms — to define 

 precisely what we mean by them, and, in the case of any particular 

 organism, to ascertain exactly which of its characters are inborn 

 and which are acquired. I know nothing in the whole range of 

 science which promises to the thinker more immediate and solid 

 results than this strangely neglected field of investigation. For 

 example, had it received the attention it deserved, it is probable 

 that the great controversy as to the transmissibility of acquired 

 traits between the Neo-Lamarckian and Darwinian schools would 

 long ago have ceased, since only after it has been definitely 

 determined whether this or that trait is inborn or acquired can the 

 fact of its transmissibility or non-transmissibility be used as an 

 argument for or against the Lamarckian doctrine. This precisely 

 the disputants have not done — an assertion I shall justify 

 presently. To deal with my subject adequately, one should have 

 the powers of a Darwin or a Herbert Spencer ; if, however, I can 

 contrive to direct attention to it, I shall be well content. 



An inborn variation may be defined as one which arises in an 

 organism owing to changes previously produced by the action of 

 the environment on the germ-cell (or pair of germ-cells), whence it 

 sprang. As inborn variations are admittedly transmissible, all 

 inborn characters must have arisen thus in the ancestry, and 



