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PHYSIOLOGY. 
BOOK II. 
CHAPTER III. 
OF SYMMETRY. 
When the elementary organs combine themselves into an 
organised structure endowed with life, they produce a body, 1. 
invariably bounded by curved lines, and, 2., having its parts 
balanced with great symmetry. In these respects they agree 
with the animal, and differ from the mineral, kingdom. 
There is no such thing as an angle in vegetation : the 
points of the most acuminated leaves, the so-called angles of 
leaves and stems, the teeth of serrated leases, are all in reality 
so many curves. Even the apparently flat surfaces of leaves 
and petals are only segments of large circles. This is a ne- 
cessary consequence of the primitive spheroidal form of vege- 
table tissue, which, in whatever way it may develope, must 
always be bounded externally by the curved sides of the 
parenchyma. 
In like manner, it will always be found, that ewery part of a 
plant is balanced by some other part. The stem is equipoised 
by the root ; one leaf or pair of leaves is counterbalanced by 
the next leaf or pair; one side of a leaf answers to another ; 
of the anthers, one lobe has its fellow on the opposite side of 
the connective ; and this kind of comparison may be carried 
into the minutest part of vegetable structure. It is true, that 
it appears in some cases of irregularity to be departed from ; 
as in Labiatae and other irregular flowers, where the balance 
among the several parts seems to be destroyed; in such 
plants as Goldfussia anisophylla, in which one of every pair 
of opposite leaves is much smaller than the other ; and in such 
leaves as those called by botanists oblique, in which one side 
of the leaf is much smaller than the other : but, even here, 
the symmetry is only destroyed in appearance. If in Labiatag 
the force of developement preponderates in the anterior 
segments of the corolla, it is counterbalanced by the fuller 
