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Updated: July 4, 2025
But medullary or fibrillary substance everywhere begins in and proceeds from the cortical; out of it nerves arise, and from them all things of the body. That this is true is proved by dissection.
Two of the doctors who had formerly attended the patient, and one of whom believed in the rupture of certain ligaments, whilst the other asserted the case to be one of medullary paralysis, had ended by agreeing that this paralysis existed, and that there was also, possibly, some ligamentary injury.
The 'olfactory', or first pair of nerves, have a double origin, namely, from the 'corpus striatum' and the base of the 'corpus callosum'. They are prolongations of the medullary substance of the central portion of the brain. They are the largest of the cerebral nerves.
From the epidermis of the gastrula a medullary tube is formed on the dorsal side, and, between this and the primitive gut, a chorda; these are the organs that are otherwise only found in Vertebrates. The formation of these very important organs takes place in the Ascidia-gastrula in precisely the same way as in that of the Amphioxus.
This clear zone separating the shadow of the dead bone from that of the living bone by which it is surrounded is conclusive evidence of a sequestrum. The medullary canal in the vicinity of the sequestrum being obliterated, is represented by a shadow of varying density, continuous with that of the surrounding bone.
If we are evolutionists at all, and grant the causal connection of ontogenesis and phylogenesis, we are forced to admit this thesis: The human soul or psyche, as a function of the medullary tube, has developed along with it; and just as brain and spinal cord now develop from the simple medullary tube in every human individual, so the human mind or the psychic life of the whole human race has been gradually evolved from the lower vertebrate soul.
Short and irregular bones have no medullary canal, only a thin shell of dense bone filled with cancellous tissue. The Right femur sawed in two, lengthwise. Experiment 5. Obtain a part of a beef shin bone, or a portion of a sheep's or calf's leg, including if convenient the knee joint. Have the bone sawed in two, lengthwise, keeping the marrow in place. Boil, scrape, and carefully clean one half.
The nutrient artery, after entering the medullary canal through a special foramen in the cortex, bifurcates, and one main division runs towards each of the extremities, and terminates at the ossifying junction in a series of capillary loops projected against the epiphysial cartilage.
The whole central marrow is merely a simple cylindrical cord which runs the length of the body, and ends equally simply at both extremities a plain medullary tube. All that we can discover is a small vesicular bulb at the foremost part of the tube, a degenerate rudiment of a primitive brain.
There is no trace in the fully-developed Ascidia of a chorda dorsalis, or internal axial skeleton. It is the more interesting that the young animal that emerges from the ovum HAS a chorda, and that there is a rudimentary medullary tube above it. The latter is wholly atrophied in the developed Ascidia, and looks like a small nerve-ganglion in front above the gill-crate.
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