188
J . M I L A I R E
FIG. 1. (a) Transverse section through a mole embryo (5 mm) at the level of the forelimb bud. Alkaline phosphatase (v. Kossa-Barger's technique). Enzyme present in the
whole of the thickened ventral ectoderm, in the proximal mesoderm of the limb bud, in
the dermatome and in the neural tube and a growing brachial nerve, (b) Transverse section through the fore-limb bud of a 9-day mouse embryo. Acid phosphatase (Gomori's
technique). Enzyme present in the whole of the thickened ventral ectoderm including,
with a higher concentration, the marginal ectoderm, (c) Frontal section through the ventral part of the fore-limb bud of a 9-day mouse embryo. Eibonucleic acid (Unna-Brachet's
technique). Large amounts of RNA present in the compact outer mesoderm and in the
inner cytoplasm of the thickening ectodermal cells (arrows), b.n.—brachial nerve; c.c.—
coelomic cavity; d—dermatome; d.Ao.—dorsal aorta; m.e.—marginal ectoderm; n.t.—
neural tube; t.v.e.—thickened ventral ectoderm.
J . M I L A I R E
FIG. 1. (a) Transverse section through a mole embryo (5 mm) at the level of the forelimb bud. Alkaline phosphatase (v. Kossa-Barger's technique). Enzyme present in the
whole of the thickened ventral ectoderm, in the proximal mesoderm of the limb bud, in
the dermatome and in the neural tube and a growing brachial nerve, (b) Transverse section through the fore-limb bud of a 9-day mouse embryo. Acid phosphatase (Gomori's
technique). Enzyme present in the whole of the thickened ventral ectoderm including,
with a higher concentration, the marginal ectoderm, (c) Frontal section through the ventral part of the fore-limb bud of a 9-day mouse embryo. Eibonucleic acid (Unna-Brachet's
technique). Large amounts of RNA present in the compact outer mesoderm and in the
inner cytoplasm of the thickening ectodermal cells (arrows), b.n.—brachial nerve; c.c.—
coelomic cavity; d—dermatome; d.Ao.—dorsal aorta; m.e.—marginal ectoderm; n.t.—
neural tube; t.v.e.—thickened ventral ectoderm.