32 



HANDBOOK OF PHYSIOLOGY 



NEUROPHYSIOLOGY I 



working in Paris and later in Copenhagen, thought 

 he had found the clue in the ganglia of the sympa- 

 thetic chain. These he envisaged as small brains in 

 wliich intercommunication between nerves could take 

 place, efTecting sympathy between various visceral 

 organs. "These ganglions . . . may be looked upon," 

 he said, "as so many origins or gcrmina dispersed 

 through this great pair of nerves, and consequently as 

 so many little brains." This ingenious but erroneous 

 theory has left its name on the structures, the sympa- 

 thetic ganglia. Winslow illustrated his te.xt with the 

 fine plates of Eustachius that had lain for so long un- 

 noticed in the \'atican Library. These plates do not 

 however show the 'small brains.' 



In following the early ideas about 'sympathy be- 

 tween the parts' it must be remembered that, although 

 so much emphasis was laid on the humors by early 

 physiologists, endocrines were unknown and conse- 

 quently their influence could not be in\oked. There 

 were, however, all down the centuries, some who held 

 that the blood was the great integrator. In the 

 eighteenth century, for example, John Hunter (179) 

 was teaching that the blood was the agent of sym- 

 pathy.'^ He was drawn to this view from his work on 

 inflammation and fevers arising from gunshot wounds 

 in the soldiers he cared for as an army surgeon in the 

 Seven Years' War with France. 



Only slowly did the concept of reflex activity gain 

 ground. Hunter's contemporary and fellow Scot, 

 Robert VVhytt, was accumulating observations and 

 making experiments that are fundamental to modern 

 physiology, although his descriptions of them are also 

 often cloaked by his terminology. In the first place 

 (180), he recognized the in\oluntary nature of pupil- 

 lary contraction and dilation and demonstrated the 

 dependence of this action on the integrity of the 

 corpora quadrigemina, thus anticipating the work of 

 Herbert Mayo (181) in the next century. He went on 



179. Hunter, John (1728-1793). Trealise on the Blood, Inflam- 

 mation and Gunshot Wounds. London : Nicol, 1 794. 



180. Whytt, Robert (17 14- 1766). An essay on the vital and 

 other involuntary motions of the animal. Edinburgh: Hamil- 

 ton, Balfour and Neill, 1751. 



181. Mavo, Herbert (1796- 1852). Anatomical and Phynological 

 Commentaries. London; Underwood, vol. I, 1822; vol. II, 

 ■ 823. 



"Samuel Taylor Coleridge's comment on some of John 

 Hunter's writings is perhaps a little harsh: "The light which 

 occasionally flashes upon us seems at other times, to struggle 

 through an unfriendly medium, and even sometimes to suffer 

 a temporary occultation." Coleridge, S. T. Hints towards the 

 Formation oj a more Comprehensive Theory of Life. Philadelphia: 

 Lea & Blanchard, 1848. 



to the study of in\oluntarv movements of voluntary 

 muscle systems in decapitated animals. The move- 

 ments of animals after their heads had been severed 

 was common knowledge to every housewife who had 

 ever killed a chicken and had attracted the attention 

 of scientists since Leonardo's day. Even in the seven- 

 teenth century Boyle C'82) had recognized the impli- 

 cations of these phenomena, realizing that "these may 

 be of great concernment in reference to the common 

 doctrine of the necessity of unceasing influence from 

 the brain, being so requisite to sense and motion." 

 Boyle's curiosity about the i^rain and its workings was 

 interwoven with his great interest in theology, al- 

 though his views on the latter did not please the 

 theologians. Dean Swift was even moved to parody 

 them in a satire called A Pious Meditation upon a Broom- 

 stick in the Slv/e of t/ie Honourable Mr. Boyle. 



Glis.son (62) had also distinguished between 'willed' 

 mo\ements and those of decapitated animals. He 

 thought the latter analogous to a class of movements 

 depending on a lower form of perception not reaching 

 the mind. One might become aware of them (^perceptio 

 sensitiva) but the\' were not ruled by the mind as were 

 \'oluntarv mo\'ements Qierceplio perceptioms^. 



Whytt's experiments (183) carried the argument 

 farther for he showed that this type of in\oluntary 

 motion could not be explained as due to the innate 

 irritability (jf muscle tissue (Haller's vis insita~), for 

 preservation of the spinal marrow was essential for it. 

 He was, however, not the first to discover that the 

 spinal cord was essential for this type of movement. 

 He had been anticipated by the Reverend Stephen 

 Hales, whose many and brilliant physiological experi- 

 ments make one wonder how^ much time he gave to 

 his parishioners in Teddington. Whytt gives full credit 

 to Hales, for he says, "The late reverend and learned 

 Dr. Hales informed me that having many years since 

 tied a ligature about the neck of a frog to prevent any 

 effusion of blood, he cut ofT its head ... the frog also 

 at this time moved its body when stimulated, but that 

 on thrusting a needle down the spinal marrow, the 

 animal was strongly convulsed and immediately after 

 became motionless." Alexander Stuart (184) repeated 



i8a. Boyle, Robert (1627-1691). Considerations touching on the 

 Usefulness of Experimental Natural Philosophy. London, 

 ,663. 



183. VVh^tt, R. Observations on the .Xalure, Causes and Cure of 

 those Disorders which are commonly called .\ervous. Hypo- 

 chondriac, or Hysteric, to which are prefixed some remarks on the 

 sympathy of the nerves. Edinburgh : Balfour, 1 765. 



184. Stuart, A. Three lectures on muscular motion, read before 

 the Royal Society in the year MDCCXXXVHI. London: 

 Woodward, 1739. 



