CHAPTER VIII 
MENDELISM (continued) 
MENDEL’s law, as stated in the preceding chapter, 
has already been found to hold good in a very large 
number of cases—cases in which all kinds of characters 
are concerned, belonging to many different species of 
animals and plants. In certain instances, however, 
complications arise, and these may be treated of in 
two main sections. 
The first kind of complication arises from the pheno- 
menon known as coupling. The essence of this pheno- 
menon consists in the existence of some kind of affinity 
occurring in the same individual between allelomorphs 
which belong to distinct pairs. In consequence of such 
an affinity exceptions are found to the rule that sepa- 
rate pairs of allelomorphs segregate independently. 
The closeness of the connection between the char- 
acters concerned shows a series of gradations in dif- 
ferent cases. In the simplest cases of all, what are 
loosely spoken of as separate characters are found on 
closer examination to be only different aspects of one 
and the same characteristic feature. These cases, then, 
offer no real exception to the rule, for only one pair of 
allelomorphs is actually concerned. Asan example, we 
197 
