Note 535 — Chapter XX

This law was foreshadowed by Reichert in 1837, when he wrote:—"We notice in our investigation of embryos of different animal forms that it is those organs, those systems, which in the fully developed individual are peculiarly perfect, that in their earliest rudiments and also throughout the whole course of their development appear with the most striking distinctness" (Müller's Archiv, p. 135, 1837). See also his Entwick. Kopf. nackt. Amphib., p. 198, 1838. So, too, Rathke notes how the elongated shape of the snake appears even in very early embryonic stages (Entwick. Natter., p. 111, 1839).