TRANSFORMISM 247 



variations that have been acquired by individual organisms in 

 response to some need, or striving, experienced by them. Thus 

 the thickened skin, or callus, that forms on parts of the hands of 

 some artisans who hold tools, are acquired structural characters. 

 We shall consider such variants by acquirement later in this 

 chapter. It is sufficient to note here that such an individual 

 variant does not usually have progeny that displays the same 

 variation — that is, an acquired character is not usually inheritable. 

 Perhaps it may be, but we shall further discuss the question later. 

 It will be seen, from the discussion of this section, that, in a great 

 number of individual organisms that belong to one local race 

 there are some that display deviations, or variations from " the 

 ordinary " in respect of any character that we measure. It is 

 quite impossible to say, by mere inspection of these individuals, 

 whether they are Mendelian variants, mutants, fluctuants at 

 random, or fluctuants by acquirement. To say what is the nature 

 of the individual variation breeding experiments, accompanied 

 by inspection, are always necessary. 



84^. Categories within the Local Race. We can now 

 attempt to make categories that are finer than the local race. All 

 such will, of course, conform to the definition of the local race 

 — just as the local races of Greenlandic, Icelandic, Irish Sea, etc., 

 cod, each has its own definition (depending on the number of 

 vertebrae) but all co'nform to the specific definition of Gadus 

 callarias. First we consider Mendelian Categories and we note 

 that it is extremely improbable that these can occur in a wild 

 population. In such individual organisms that display Mendelian 

 inheritance there are characters that are reassorted at each act 

 of sexual reproduction. There is an ensemble of characters, 

 £", displayed by all the individuals and there are the *' loose " 

 " allelomorphic " Mendelian characters, a and 6, c and d^ e and 

 /, etc. As the results of promiscuous matings these characters 

 become reassorted in each generation so that we may have indivi- 

 duals displaying Eace, Eaef, Bade, Eadf, Ebce, 

 Ebcf, Ebdc, Ebdf, that is all the possible combinations of 

 the Mendelian characters (that do not involve " lethal " results). 

 This is what we should expect to find in a wild population — the 

 random reassortments, or combinations of the characters, but no 

 one category of individuals, all of them displaying the same 

 combination of characters. We can make such a category by 



