15.20
FIG. 3. Change of colour of Janus green showing reduction gradients in a late blastula
{A^-At) and a gastrula {B x -B^). Large dots, blue; small dots, red; no dots, the colour has
faded. Figures indicate time of observations. In B^-Bq the colour observed only in the
ectoderm (from Hörstadius, 1952).
fS t SO
16,15
FIG. 4. Reduction gradients in isolated vegetal halves (from Hörstadius, 1952).
ANIMALIZATION AND VEGETALIZATION
155
FIG. 3. Change of colour of Janus green showing reduction gradients in a late blastula
{A^-At) and a gastrula {B x -B^). Large dots, blue; small dots, red; no dots, the colour has
faded. Figures indicate time of observations. In B^-Bq the colour observed only in the
ectoderm (from Hörstadius, 1952).
fS t SO
16,15
FIG. 4. Reduction gradients in isolated vegetal halves (from Hörstadius, 1952).
ANIMALIZATION AND VEGETALIZATION
155