germal

In the animal or soul-world (anima, psyche) beginning with the oviparous orders, or rather with the bird-class among these, the above germal speck is, as is well known, visible, being a diminutive flake, rag or shred of skin, commonly called treddle, a pellicle floating between the yolk and the white of the egg, where it has been deposited by the male parent.

1871, J. Filmer Emmett, The Theory of Germs, page 6