328
EDGAR
ZWILLING
(1949) and Bretscher and Tschumi (1951) in experiments on the effect
of anti-mitotics on development of the hind limb of Xenopus. There may
be a proportional reduction of the entire limb under some circumstances.
Under others the long bones are relatively little affected by the treatment
but the digits do suffer marked reduction. The reduction was related to
diminution in the limb paddle area. There was considerable consistency
in the pattern of reduction; as the paddle area decreased the digits were
eliminated in this order; digit I, then II and V, then III and IV. There
was more tendency for an entire digit to be eliminated than for several
to be reduced in size. Bretscher interpreted his observations as a competition between digits with the central digits (III and IV) evincing
greatest dominance. For lesser reductions there was a somewhat similar
competition among the phalanges of a given digit. Somewhat similar
findings were reported for polydactylous and normal chicken limbs
(Bretscher, 1950).
While it is beyond the scope of this paper to enter into a detailed
discussion of aberrant limb morphogenesis and the situations under
which anomalies are produced it is difficult to conclude without some
mention of these phenomena. A number of them have been brought
into the discussion under one or another of the previous headings:
amelia (winglessness), Polydactyly and various other conditions have
been mentioned. There is considerable literature concerned with anomalous growth patterns mediated by various experimental conditions
(Landauer, 1954; Jost, 1951, 1953; Ancel, 1950) as well as by mutant
genes (Landauer, 1954; Hütt, 1949; Rostand, 1955). Related to such
aspects of development are experiments on nutritional requirements of
various bones grown in culture (Kieny, 1958) as well as the effects
of various metabolites on bone growth (Fell, 1954; Fell and Mellanby,
1952). In an attempt to relate the current of early limb morphogenesis,
I may have done an injustice in not treating more fully these aspects of
limb development.
References
Amprino, R., and Camosso, M. (1955a). J. exp. Zool. 129, 453-493.
Amprino, R., and Camosso, M. (1955b). C.R. Ass. Anat. 42, 197-203.
Amprino, R., and Camosso, M. (1956). Arch. Biol. 67, 613-633.
Amprino, R., and Camosso, M. (1958a), Experientia 14, 241-245.
Amprino, R., and Camosso, M. (1958b). C.R. Ass. Anat. 45, 93-102.
Amprino, R., and Camosso, M. (1958c). Roux Arch. EntwMech. Organ 150, 509-541.
Amprino, R., and Camosso, M. (1959). Arch. Anat. micr. (in press).
Ancel, P. (1950). 'La Chimiotératogénése.' Realisation de Monstruosités par des
Substances Chimiques chez les Vertebres. Paris (G. Doin).
Balinsky, Β. I. (1931). Roux Arch. EntwMech. Organ 123, 565-648.
Balinsky, Β. I. (1935). Zool. Jb. 9 54, 327-348.
Balinsky, Β. I. (1956). Proc. nat. Acad. Sei. 42, 781-785.
EDGAR
ZWILLING
(1949) and Bretscher and Tschumi (1951) in experiments on the effect
of anti-mitotics on development of the hind limb of Xenopus. There may
be a proportional reduction of the entire limb under some circumstances.
Under others the long bones are relatively little affected by the treatment
but the digits do suffer marked reduction. The reduction was related to
diminution in the limb paddle area. There was considerable consistency
in the pattern of reduction; as the paddle area decreased the digits were
eliminated in this order; digit I, then II and V, then III and IV. There
was more tendency for an entire digit to be eliminated than for several
to be reduced in size. Bretscher interpreted his observations as a competition between digits with the central digits (III and IV) evincing
greatest dominance. For lesser reductions there was a somewhat similar
competition among the phalanges of a given digit. Somewhat similar
findings were reported for polydactylous and normal chicken limbs
(Bretscher, 1950).
While it is beyond the scope of this paper to enter into a detailed
discussion of aberrant limb morphogenesis and the situations under
which anomalies are produced it is difficult to conclude without some
mention of these phenomena. A number of them have been brought
into the discussion under one or another of the previous headings:
amelia (winglessness), Polydactyly and various other conditions have
been mentioned. There is considerable literature concerned with anomalous growth patterns mediated by various experimental conditions
(Landauer, 1954; Jost, 1951, 1953; Ancel, 1950) as well as by mutant
genes (Landauer, 1954; Hütt, 1949; Rostand, 1955). Related to such
aspects of development are experiments on nutritional requirements of
various bones grown in culture (Kieny, 1958) as well as the effects
of various metabolites on bone growth (Fell, 1954; Fell and Mellanby,
1952). In an attempt to relate the current of early limb morphogenesis,
I may have done an injustice in not treating more fully these aspects of
limb development.
References
Amprino, R., and Camosso, M. (1955a). J. exp. Zool. 129, 453-493.
Amprino, R., and Camosso, M. (1955b). C.R. Ass. Anat. 42, 197-203.
Amprino, R., and Camosso, M. (1956). Arch. Biol. 67, 613-633.
Amprino, R., and Camosso, M. (1958a), Experientia 14, 241-245.
Amprino, R., and Camosso, M. (1958b). C.R. Ass. Anat. 45, 93-102.
Amprino, R., and Camosso, M. (1958c). Roux Arch. EntwMech. Organ 150, 509-541.
Amprino, R., and Camosso, M. (1959). Arch. Anat. micr. (in press).
Ancel, P. (1950). 'La Chimiotératogénése.' Realisation de Monstruosités par des
Substances Chimiques chez les Vertebres. Paris (G. Doin).
Balinsky, Β. I. (1931). Roux Arch. EntwMech. Organ 123, 565-648.
Balinsky, Β. I. (1935). Zool. Jb. 9 54, 327-348.
Balinsky, Β. I. (1956). Proc. nat. Acad. Sei. 42, 781-785.