126
R. J.
GOSS
(Umanski, 1938b). In general, therefore, there is a correlation between
the kind of regenerate produced and the source of the muscle from which
it develops.
4. Skin
Analysis of the role of skin in appendage regeneration involves
consideration of two separate problems, namely, its necessity for the
promotion of limb regeneration, and its possible effect on the organisation of the regenerating structure. With reference to the former aspect,
it has been shown that skinless limbs, inserted into the body musculature
or the abdominal cavity, cannot regenerate (Polezhaev and Favorina,
1935; Morosow, 1938; Goss, 1956c, e). Indeed, if a limb is allowed to
undergo partial regeneration prior to this treatment, its growth is
arrested at that particular stage. Hence, skin is essential for the initiation
and sustained growth of limb regenerates.
To determine if the skin, like muscle and bone, directs the morphogenesis of regenerating structures, various investigators have performed
numerous transplantation experiments. If the skin is removed from a
limb, and replaced by that from another area of the body, regeneration
is sometimes absent but usually gives rise to a new limb. Belly skin,
transplanted to limbs, permitted the regeneration of normal or abnormal
limbs according to the experiments of Taube (1921, 1923), Holzmann
(1939a), Rose and Seller (1946), and Wolff and Wey-Schué (1952).
Holzmann (1939a) also obtained limb regenerates from extremities
enveloped by skin from the dorsal side of the body. When the integument
of the limb was replaced by head skin, limb regeneration occurred in
most cases described by Polezhaev and Favorina (1935), Holzmann
(1939a, b), and Lecamp (1951), but Umanski (1937) reported no regeneration under these conditions.
Skin from a part of the body normally capable of regeneration, such
as the tail, usually does not influence the kind of outgrowth produced.
Thus, Holzmann (1939a) reported the regeneration of limbs from
extremities covered by tail skin. However, similar experiments by Glade
(1957) yielded tail-limb chimerae (probably the result of the inadvertent
incorporation of tail mesoderm in the graft). The results of comparable
experiments on tail regeneration have been consistent with studies on
limbs. Thus, if tail skin is replaced by body skin, tails are regenerated;
but if limb skin is grafted to tails, there are regenerated tails sometimes
possessing digits (Luther, 1948; Trampusch, 1958b). In general, however, regeneration proceeds in accordance with the developmental
potentialities of the underlying tissues comprising the limb stump,
irrespective of the kind of skin replacing that previously removed from
the extremity.
R. J.
GOSS
(Umanski, 1938b). In general, therefore, there is a correlation between
the kind of regenerate produced and the source of the muscle from which
it develops.
4. Skin
Analysis of the role of skin in appendage regeneration involves
consideration of two separate problems, namely, its necessity for the
promotion of limb regeneration, and its possible effect on the organisation of the regenerating structure. With reference to the former aspect,
it has been shown that skinless limbs, inserted into the body musculature
or the abdominal cavity, cannot regenerate (Polezhaev and Favorina,
1935; Morosow, 1938; Goss, 1956c, e). Indeed, if a limb is allowed to
undergo partial regeneration prior to this treatment, its growth is
arrested at that particular stage. Hence, skin is essential for the initiation
and sustained growth of limb regenerates.
To determine if the skin, like muscle and bone, directs the morphogenesis of regenerating structures, various investigators have performed
numerous transplantation experiments. If the skin is removed from a
limb, and replaced by that from another area of the body, regeneration
is sometimes absent but usually gives rise to a new limb. Belly skin,
transplanted to limbs, permitted the regeneration of normal or abnormal
limbs according to the experiments of Taube (1921, 1923), Holzmann
(1939a), Rose and Seller (1946), and Wolff and Wey-Schué (1952).
Holzmann (1939a) also obtained limb regenerates from extremities
enveloped by skin from the dorsal side of the body. When the integument
of the limb was replaced by head skin, limb regeneration occurred in
most cases described by Polezhaev and Favorina (1935), Holzmann
(1939a, b), and Lecamp (1951), but Umanski (1937) reported no regeneration under these conditions.
Skin from a part of the body normally capable of regeneration, such
as the tail, usually does not influence the kind of outgrowth produced.
Thus, Holzmann (1939a) reported the regeneration of limbs from
extremities covered by tail skin. However, similar experiments by Glade
(1957) yielded tail-limb chimerae (probably the result of the inadvertent
incorporation of tail mesoderm in the graft). The results of comparable
experiments on tail regeneration have been consistent with studies on
limbs. Thus, if tail skin is replaced by body skin, tails are regenerated;
but if limb skin is grafted to tails, there are regenerated tails sometimes
possessing digits (Luther, 1948; Trampusch, 1958b). In general, however, regeneration proceeds in accordance with the developmental
potentialities of the underlying tissues comprising the limb stump,
irrespective of the kind of skin replacing that previously removed from
the extremity.