SYMMETRY IN TRANSPLANTED LIMBS 41 
The results are not altogether conclusive, though they point 
to the correctness of the hypothesis. Twenty-three operations 
were done, of which seventeen yielded positive results. Ten 
cases harmonize with the hypothesis; four are doubtful, and three 
are contrary to it (figs. 61 and 62). When the difficulty of ex- 
actly estimating the degree of rotation is considered, many ap- 
parent exceptions must be expected, and a far greater number of 
experiments would be necessary to eliminate statistically the 
effect of this uncertainty. As a matter of fact, the records of the 
cases classed as surely exceptional give evidence that the amount 
A iso° 
V 
Fig. 60 Diagram showing difference in amount of rotation in two sets of 
experiments. The circle represents the left limb bud and the arrow the direction 
of rotation. A,D,P, V, the direction of the cardinal points of the embryonic 
body, anterior, dorsal, posterior, and ventral, respectively. 
of rotation at the time of operation was probably not correctly 
estimated, for the first direction of pointing (p. 11) in all of 
these cases is not according to expectation. 
The thirty-seven cases in which the wound bed was not entirely 
cleaned of mesoderm may now be considered. These show a 
marked contrast to those with cleaned wounds, inasmuch as there 
are very few reduplications and a very large proportion of normal 
non-reversed limbs. Thus out of twenty cases which yielded 
positive results eighteen or 90 per cent are normal, as compared 
with 23.8 per cent (ten cases) in the clean-wound class. Only one 
case (5 per cent) had a reduplicated limb, as compared with 
thirty-one duplicities (73.8 per cent) in the clean-wound class. 
