III. REGENERATION OF VERTEBRATE
APPENDAGES
125
sequently produced regenerates. Simple addition of tail muscles to
extremities has resulted in the development of tail regenerates (Liosner,
1937a) or tail-limb chimerae (Okada, 1936; Glade, 1957). When tail
muscles replace limb muscles, subsequent regenerates are tail-like,
limb-like, or mixtures of the two (Liosner and Woronzowa, 1935, 1936,
1937; Woronzowa, 1939). Liosner (1937b) reports the production of tail
regenerates following substitution of limb skeleton by tail musculature,
while Savchuck (1938) obtained composite tail-limb regenerates under
similar conditions. Monroy and Oddo (1943), after transplanting caudal
musculature in place of the muscles and bones of limbs, described the
development of regenerates of mixed tail and limb types. Conversely, it
has been demonstrated by Liosner and Woronzowa (1935) that thigh
muscles transplanted to tails cause the formation of digits from the
subsequently produced tail regenerates.
From the foregoing experimental results, it is apparent that muscles
from nonregenerating areas of the body do not influence the morphogenesis of regenerates. However, muscular tissues of extremities exert
a determining effect upon the developing blastemas. The regenerates
resulting from such limbs frequently exhibit attributes characteristic of
both host and donor organ, reflecting the effects of all tissues present in
the stump.
In other experiments, in which the appendages are exposed to
inhibitory doses of X-rays prior to receiving unirradiated muscle
implants from other sources, the regenerates produced conform to the
origin of the transplanted muscle. It has been demonstrated by
Umanski (1937), Thornton (1942) and Trampusch (1951) that limb
musculature, when transplanted to previously irradiated limbs, can give
rise to outgrowths which, although always abnormal, possess definitely
limb-like characteristics. Recent experiments by Skowron and Roguski
(1958) have resulted in the regeneration of abnormal limbs from X-rayed
extremities injected with dissociated cell suspensions of muscle and
connective tissue from healthy limbs. Comparable experiments involving
the implantation of healthy tail muscle into X-rayed limbs have
resulted in tail-like regenerates (Umanski, 1937; Thornton, 1942;
Skowron and Roguski, 1958). However, Liosner (1947) replaced axolotl
limb muscles with tail muscles and obtained mostly tail-like regenerates
plus some which exhibited limb qualities. It is possible that the latter
results may be attributed to the participation of unirradiated limb
tissues which migrated to the level of amputation from more proximal
unexposed regions of the limb. When nonregenerating muscles from the
backs of the axolotls were transplanted to the thighs from which the
limb muscles had been removed, either no regeneration occurred, or
undifferentiated protusions, sometimes resembling fins, were formed
APPENDAGES
125
sequently produced regenerates. Simple addition of tail muscles to
extremities has resulted in the development of tail regenerates (Liosner,
1937a) or tail-limb chimerae (Okada, 1936; Glade, 1957). When tail
muscles replace limb muscles, subsequent regenerates are tail-like,
limb-like, or mixtures of the two (Liosner and Woronzowa, 1935, 1936,
1937; Woronzowa, 1939). Liosner (1937b) reports the production of tail
regenerates following substitution of limb skeleton by tail musculature,
while Savchuck (1938) obtained composite tail-limb regenerates under
similar conditions. Monroy and Oddo (1943), after transplanting caudal
musculature in place of the muscles and bones of limbs, described the
development of regenerates of mixed tail and limb types. Conversely, it
has been demonstrated by Liosner and Woronzowa (1935) that thigh
muscles transplanted to tails cause the formation of digits from the
subsequently produced tail regenerates.
From the foregoing experimental results, it is apparent that muscles
from nonregenerating areas of the body do not influence the morphogenesis of regenerates. However, muscular tissues of extremities exert
a determining effect upon the developing blastemas. The regenerates
resulting from such limbs frequently exhibit attributes characteristic of
both host and donor organ, reflecting the effects of all tissues present in
the stump.
In other experiments, in which the appendages are exposed to
inhibitory doses of X-rays prior to receiving unirradiated muscle
implants from other sources, the regenerates produced conform to the
origin of the transplanted muscle. It has been demonstrated by
Umanski (1937), Thornton (1942) and Trampusch (1951) that limb
musculature, when transplanted to previously irradiated limbs, can give
rise to outgrowths which, although always abnormal, possess definitely
limb-like characteristics. Recent experiments by Skowron and Roguski
(1958) have resulted in the regeneration of abnormal limbs from X-rayed
extremities injected with dissociated cell suspensions of muscle and
connective tissue from healthy limbs. Comparable experiments involving
the implantation of healthy tail muscle into X-rayed limbs have
resulted in tail-like regenerates (Umanski, 1937; Thornton, 1942;
Skowron and Roguski, 1958). However, Liosner (1947) replaced axolotl
limb muscles with tail muscles and obtained mostly tail-like regenerates
plus some which exhibited limb qualities. It is possible that the latter
results may be attributed to the participation of unirradiated limb
tissues which migrated to the level of amputation from more proximal
unexposed regions of the limb. When nonregenerating muscles from the
backs of the axolotls were transplanted to the thighs from which the
limb muscles had been removed, either no regeneration occurred, or
undifferentiated protusions, sometimes resembling fins, were formed