1. Lillie schreibt (1919, S. 261): ?The primary change in activation is not something visible in a morphological sense; the visible cortical changes are due to activation and are obviously specific for the kind of egg concerned; hence the considerable variety that they exhibit in different animal groups. Some theories of artificial activation have erred in respect to undue emphasis on the morphological change as though it were primary instead of being secondary or even tertiary.?