Spinal cord extends from the back of the hind brain(Medulla oblongata) to the back of the stomach or lumbar region, through the neural canal of the vertebral column. It is almost cylindrical in shape. Unlike the brain, the white matter is towards periphery while grey matter is towards the center of the spinal cord. The myelinated axons leave the spinal cord from both sides of the vertebral column. See fig-11. The role of the spinal cord in nervous control was studied largely by the experimentalists of the sixteenth and seventeenth centuries. They found that the Greeks concept of control by the brain was erroneous. Animals were shown to have the ability to respond to stimuli even when the brain was removed. "Leonardo da Vinci" 91452-1519) and 'Stephen Hales' (1677-1771) both recorded the survival of frogs whose brain had been destroyed. The animal still produced muscular movements if its skin was pinched or pricked. Both observers further recorded that the animal died as soon as spinal cord was damaged by pushing a needle down it.

Such evidence suggested that the spinal cord was not simply a trunk
road for instructions from the brain, but might be a control center in its
own right.

Figure-13 shows you that nerves attached to the spinal cord have two types of connections or roots - One to the back or dorsal side and other to front or the ventral side of cord. The experimental work of two men, Charles