118 THE FORMATION OF VARIETIES. 



instead of increasing it in parts only; then, in one ball, 

 relax the pressure fully, in one part only; and then in 

 other balls, relax the pressure in the same just-men- 

 tioned part, but relax it less and less, in a descending 

 degree, in the several, remaining balls. 



Having done this, conformably to direction, you will 

 have varieties, of the, originally, one kind of ball, ex- 

 actly analogous to varieties of a species under domes- 

 tication. The compression, of the ball, represents 

 degeneration; the elasticity, displayed upon relaxa- 

 tion of the pressure, corresponds to reversion. The 

 disproportionate compression, and disproportionate 

 relaxation, are respectively analogous to dispropor- 

 tionate Reversion, and to disproportionate degener- 

 ation, in organisms. The balls, in their original, 

 normal state of expansion, represent the original, 

 normal type of a species. As the restraint, upon the 

 several balls, constraining them to a shape, not in 

 harmony with the natural properties of their matter, 

 is abnormal; so, the disproportionate development of 

 varieties, is abnormal, as the retention, of their parts, 

 at any stage short of full, complete reversion, is in 

 derogation of the one, true ratio of their development. 

 In the case of an organism, there is a crucial test, 

 demonstrating most positively, that any constraint to 

 a shape, short of the full development of all the posi- 

 tive features of the species, is injurious to physiologi- 

 cal integrity. 



The compression, of the ball, to half its size, does 

 not exactly represent the degeneration in species, under 

 nature. For the compression, above mentioned, is im- 



