PRELUDE TO ELECTRO-PHYSIOLOGY

Let us first consider the ideas of Francis Glisson (1) in the middle of the seventeenth century. Glisson believed that all the ‘fibres’ of the organism, not only muscle fibres, had a special property of irritability causing them to respond by contraction to external or internal stimuli; by ‘fibre’ he understood a gossamer-like but strong and elastic thread. He recognised three types of impulse: one intrinsic, due to the fibres’ own structure and independent of the nervous system; the second transmitted in the spiritus vitalis through the blood; the third in the spiritus animalis conveyed through the nerves. We have already mentioned Glisson's acceptance of the standpoint that the cause of contraction could not be inflation of the muscle by animal or vital spirits. Bastholm (1) has well described the intricacies of Glisson's theory; besides the motus naturalis, dependent on the intrinsic properties of the fibre and quite independent of the nervous system, he postulated the motus sensitivus externus due to the nerve stimulation, and the motus sensitivus internus, due to the action of the supreme regulatory principle phantasia upon the nerve. It should be remembered that William Harvey, from his embryological studies, had a little earlier deduced that irritability was an intrinsic property of living tissue, since the heart and other muscles in a foetus could contract before the brain appeared.