SYMMETRY IN TRANSPLANTED LIMBS 83 
ment, and with an equal number of experiments in all of the six- 
teen possible classes, the expectation would be that only 25 
per cent of the homogeneous and 75 per cent of the heterogeneous 
would be normal. This corresponds closely to the figures 27.7 
and 72.9, respectively, found in table 5. 
As regards the question of equipotentiality, the results of these 
experiments are equally striking. The two homogeneous com- 
binations which, according to expectation, should yield normal 
limbs did so. Thus two ventral halves yielded normal limbs in 
all six experiments, as did two dorsal halves in five out of 
seven. In three cases of disharmonic homogeneous combination 
normal limbs developed by resorption of the reduplicating bud; 
two of these were from two anterior halves and one from two 
posterior. Two further cases of normal limbs from two anterior 
halves developed without external evidence of resorption. While 
the last five, if interpreted according to the rules, can only be 
accepted as evidence of equipotentiality in so far as they show 
that a whole limb can develop out of a single half bud, the 
others show that two half buds which are alike except that they 
are from opposite sides of the body may give rise, when harmonic, 
to a single normal limb. 
GENERAL DISCUSSION 
In this section the following questions will be considered: 
1) the foundation of the rules of symmetry; 2) the mode of repre- 
sentation of symmetric relations in the limb rudiment; 3) the 
formation of reduplications; and 4) form regulation and function 
in transplanted limbs. 
E. The rules of symmetry. 
The validity of the rules of symmetry which have already 
been stated in the introduction (p. 4) will best be realized by 
considering the results of the several experiments in tabular 
form (table 6). Conformity is shown most strikingly in the 
heterotopic group, where there is only a single apparent excep- 
tion in forty-five cases; and this exception, as already pointed 
out, is probably due to an error in recording the operation. 
