MERISTIC VARIATION 73 



SECTION VI IMPORTANCE OF MERISTIC VARIATION 



Nothing is of more direct benefit to man than the stooling of 

 grain, and the doubling of flowers is of prime importance to 

 students of the beautiful. Digital variation, and indeed most of 

 the examples among animals, are not only of no practical use but 

 they constitute deformities that would at once be eliminated from 

 the fields of any intelligent stockman. 



Their study is, however, useful to the student in two ways : 

 first, as showing him that freaks are by no means uncommon 

 and therefore not to be specially prized ; and second, to show 

 the manner in which variation operates and the size of the unit 

 involved, together with something of its relations to other and 

 similar units in the same body. The careful student will not, 

 therefore, waste his time in trying to establish a race of solid- 

 hoofed hogs the first time a specimen of the kind turns up in 

 his yard, but he will utilize the information afforded in meristic 

 variation generally to advance his understanding of the manner 

 in which variation behaves and of the relations that obtain between 

 the several parts of a highly differentiated body. 



The purpose at this time is to secure a mass of characteristic 

 facts on which future studies may be based. Most of the dangers 

 of erroneous procedure in this field arise from a paucity of well- 

 authenticated instances and from restricted views of their real 

 significance. 



Summary. Meristic variation refers to deviations in the plan 

 or pattern on which the organism is built. Its central thought is 

 symmetry. Symmetry may be radial with the members identical, 

 or it may be bilateral with opposite members, as optical images 

 the one of the other. Distinctions of right and left arise fr6m 

 those of dorsal and ventral, and have reference to the relation of 

 the individual to the outside world. Organs symmetrically placed 

 may or may not have a symmetry of their own, but the ten- 

 dency is for a part to establish some kind of symmetry within 

 its own members. 



When parts are multiplied they may be like the other mem- 

 bers of the series in which they arise, or they may imitate those 

 of neighboring series (homoeosis). Repeated parts are especially 



