SYMMETRY IN TRANSPLANTED LIMBS 71 
posed of two similar halves, while the other half are heterogene- 
ous. Of the former, six belong to the disharmonic group and 
only two to the harmonic, while of the latter the reverse is the 
case, a circumstance that affects the proportionate results of 
the experiments. 
The effect of removal of the various halves of the limb rudiment 
has already been described (Harrison, '18). As shown bj^ such 
experiments, any half of the limb bud can give rise to a whole 
limb, though quantitatively the material is eccentrically distrib- 
uted, there being more limb-forming tissue in the dorsal and 
anterior halves than in the ventral and posterior halves, respec- 
tively. Accordingly, four of the homogeneous combinations 
would have somewhat less than the normal amount of tissue, 
while four would have a little more. In the later experiments 
an attempt was made to compensate for this by not cutting the 
area exactly in half. 
Owing to the large number of combinations in the experiments, 
it has not been possible to perform a sufficient number of each, 
for accurate statistical treatment. The number is sufficient, how- 
ever, to compare the more comprehensive groups; for instance the 
homogeneous with the heterogeneous and the harmonic with the 
disharmonic. 
Seventy-nine operations were done, sixty-eight healing success- 
fully. Badly defective limbs developed in but four cases, so that 
sixty-four remain for the purpose of the analysis. These experi- 
ments are summarized in table 4. 
From the results of transplanted whole limbs we should expect 
the following to take place; the harmonic combinations should 
give rise to simple normal limbs, the disharmonic to reduplica- 
tions. The homogeneity or heterogeneity of the combination 
should not be expected to make any difference in view of the other 
tests of the equipotentiality of the system. These expectations 
were in the main realized, probably in fifty-five out of the sixty- 
four cases (85.9 per cent) (table 7). There are, however, sources 
of confusion, which in certain cases make several interpretations 
possible, and which for this and other reasons must not be over- 
looked. For example, it is known from experiments with whole 
