SYMMETRY IN TRANSPLANTED LIMBS 
15 
one, which yielded an imperfect appendage. They need not be 
considered separately here, though a more extensive series of 
experiments of the latter type would probably yield different 
and more interesting results. 
The limb buds transplanted to the flank of the embryo are 
placed in an environment similar to that of the normal fore limb, 
as far as relations to the body wall and muscle plates are con- 
cerned, though they lack the specific blood supply and innerva- 
tion of the limb region. Consequently, a very high percentage 
TABLE 1 
Heterotopic transplantations. Summary o 
/ expe7 
iments 
NUMBER OF 
EXPERIMENTS 
SIXGLE LIMBS 
NOT REVERSED 
SINGLE LIMBS 
REVERSED 
REDUPLICATED 
Total 
Posi- 
tive' 
Num- 
ber 
Percent 
Num- 
ber 
Per 
cent 
Num- 
ber 
Per 
cent 
Hom dd 
19 
31 
28 
60 
7 
12 
10 
16 
3 

8 
1(?)= 
42.8 
00.0 
80.0 
6.3(?) 

11 

7 
00.0 
91.7 
00.0 
43.8 
4 
1 
2 
8 
57.1 
Horn, dv 
Het. dd 
8.3 
20.0 
Het. dv 
50.0 
Total 
138 
45 
12 
26.7 
18 
40.0 
15 
33.3 
Average of percentages 
32.3 
33.9 
33.9 
1 Excluding all cases where death occurred prematurely or where the grafted 
limb was resorbed or remained rudimentary. Percentages in all tables have been 
calculated on the basis of positive experiments. 
2 There is evidence that in this case thfere was an error in the orientation of 
the bud and that it should therefore be classed in the group het. dd. 
of cases yielded only abortive limbs, and those that did develop 
rarely showed any functional activity. ^^ There is also greater 
difficulty in securing good healing of wounds in the intermediate 
region, so that a larger proportion of the cases died early. In 
many of these cases there is obviously some interference with 
the development of the pronephric duct, which becomes blocked. 
The secretion which accumulates causes the formation of a cyst 
of considerable size, which may interfere with the development 
of the limb bud. 
The results of the experiments are summarized in table 1. 
11 Cf. Detwiler, '19 and '20. 
