Oyster and Earthworm
The oyster could be such a clever fellow if he did not exude the calcium salt forces into an external shell instead of retaining them as an inner capacity. The thinking process, the forming of fixed inner images and concepts is an inner Salt process, which belongs to the formative tendencies of the head pole of the human being. At one point Steiner mentions that we think with our skeletons, which are also an effect of the forming and hardening force radiating from the head into the body. To the doctors it was revealed that the humble shell-less earthworm exudes calcium into the body of the earth helping to give it formative forces, so that what the oyster does for itself, the earthworm does for the benefit of the whole earth.
“In previous lectures, I have pointed to a process which can help us read the human processes from the activities of Nature. I have referred to what we may simply term the formative process of the oyster shell. In that process, we pass from the resultant of combining carbon with potassium, to the combination with calcium. But the effects that would follow the combination of carbon and calcium, without any third element, are much modified by the powerful phosphoric forces at work in the oyster shell. All these forces are mingled in the oyster shell with certain others, found in the marine environment. And the consideration of the formation of these shells, leads us a step further into the relationship between external nature and man. Let us pass downwards through the watery zone round the earth, and come to the actual earth formation, to what we might term the solidification. (We should not have any hesitation today in referring to earth, water, air and fire — if the terms linked in association had not become unfashionable and unpopular, as having been used by ignorant folk of old! But among ourselves, surely, we are at liberty to refer to these things.) This solid structure of earth has also its counterpart in the cosmos; and this is the realm of vitalisation, the source of all life formation. The vital forces come to us from a further distance even than the chemical, and within the extra-human earth — that is in the “earthly sphere” proper — they are completely killed.
Moreover, our earth would come to exuberant growth and would form ebullient living outgrowths of carcinomatous nature, if this hypertrophy were not checked by the workings of the extra-telluric Mercury (the planet) which develops the mercurial process. It is of value, even once to have realised and thought over this matter. The formative force active in earth formation, in the formation of earth substance, we may see retarded as it were, held back at an earlier stage, in the formation of the oyster shell. The Oyster shell is withheld from becoming part of the earth’s structure, by its ancient and persistent link with the sea, and thus preserves the formative earth process at a more primitive stage when it solidifies. Earthworms cannot do this as they have no shell. But the same forces proceed from them ceaselessly and therefore it is entirely true to say that if there were no earthworms, there would be no formative forces inside the earth. These worms play a leading role in the process of earth formation. The whole world of the earthworms represents something that passes beyond the formation of the oyster’s shell, and has just as much a relationship to the whole earth as the oyster shell. And so the shell formation is suppressed and there arises instead the processes in arable soil and all related processes.”
R. Steiner, Spiritual Science and Medicine, Lecture 11, 31 March 1920, CW312