THE HISTORICAL DEVELOPMENT OF NEUROPHYSIOLOGY 



central relay. Descartes recognized, however, that 

 perhaps some of these actions lay outside the control 

 of the will, citing as examples involuntary blinking 

 and the withdrawal of the hand on burning. 



To neurophysiologists Descartes bequeathed an- 

 other seed — what was later to be known as the re- 

 ciprocal innervation of antagonist muscles. In order 

 to ensure that while animal spirits were flowing 

 into one set of muscles the opposing set should relax, 

 he argued that the latter must have their supply of 

 spirits blocked and he postulated that this must be 

 eflTected by valves. Whether or not he was influenced 

 in his thinking by Harvey's explanation of the 

 valves of the veins is not known, although he was 

 certainly aware of, and had commented on, Harvey's 

 discoveries.^ Descartes was a member of what a sub- 

 sequent irreverent generation was to call 'the bal- 

 loonists.' Apparently unaware of Borelli's experiments, 

 he thought the animal spirits to be "like a wind or a 

 verv subtle flame" and that "when they flow into a 

 muscle they cause it to become stiff and swollen, just 

 as air in a balloon makes it hard and stretches the 

 substance in which it is contained." 



A young contemporary of Descartes, though less 

 directly influenced bs' him than was Borelli, was Wil- 

 liam Croone who was working on muscle action. He 

 too thought that the nervous 'juice' must interact in 

 some way with the muscle (26). The "spiritous liquid" 

 flowed in, mixed with "the nourishing juice of the 

 muscle," and then the muscle "swell'd like a Bladder 

 blown up. " Later (27} Croone was to modify this to 

 a number of small bladders for each muscle fiber. 

 Just as Borelli had been a founding member of a 

 scientific society, so was Croone. He was one of the 

 original group who in England formed the Royal 

 Society, a society which unlike the Cimento has con- 

 tinued to flourish and in which to this day eminent 

 .scientists not only discuss but demonstrate their ex- 

 periments before the members. The Royal Society 

 has several distinguished lectureships, among which 

 is the Croonian Lecture founded by the widow of 

 William Croone. 



The Royal Society of London received its charter in 

 1662, being founded for the promotion of "Natural 

 Knowledge,' and it numbered among the founding 

 members many who.se contributions are fundamental 



26. Croone, William (1633-1684). De raiione motus muscu- 

 lorum (published anonymously). London: Hayes, 1664. 



■27. Croone, W. An Hypothesis of the Structure of the Muscle, and 

 the Reason of its Contraction. Hooke's Philosophical Collec- 

 tions, No. II. London, 1675. 



to physiolog)-. The mo\ing spirit was Robert Bovle, 

 the 'father of chemistry' (whose first published work 

 was, however, on Seraphick Love). Famous for his law 

 (28) of gaseous pressures, he made his most directly 

 physiological experiments on the respiration of ani- 

 mals. It was still many years before physiologists were 

 to elucidate the efTects of anoxia on the nervous 

 system, and another hundred years were to pass before 

 Priestley's and Lavoisier's work on oxygen, but Boyle, 

 by using an ingenious compression chamber, demon- 

 strated that air is essential for life. Almost unnoticed 

 at the time, but since then perhaps overpraised, were 

 the observations of John Mayow (29) on the chem- 

 istry of respiration. His publication preceded (al- 

 though his work was contemporary with) the some- 

 what similar experiments of the Accademia del 

 Cimento. 



In the early seventeenth century emphasis on the 

 search for a chemical foundation for living phe- 

 nomena characterized for the most part work in 

 Holland and England in contrast to the physical and 

 mathematical approach of the Italians and the 

 French. The two contrasting .schools of thought were 

 long to be known by the clumsy names of the iatro- 

 chemical and iatromechanical schools. latrochemis- 

 try, on the rather shaky foundations given to it by 

 van Helmont (1577-1644) and by Sylvius (de La Boe) 

 (1614-1672), provided the approach to the study of 

 the nervous system of Thomas Willis, Sedleian Pro- 

 fessor of Natural Philosophy at Oxford (30). Willis, 

 whose clinical achievements outshone his scientific 

 acumen, is recognized in neurology for his description 

 of the circle of Willis and his dissection of the spinal 

 accessory nerve. (Galen had identified only seven 

 pairs of cranial nerves.) Willis was a close colleague at 

 Oxford of Richard Lower, the Cornishman, champion 

 of the theory that spirits flowing into the heart from 



28. Boyle, Robert (162 7-1 691). .\ew experiments physico- 

 mechamcal, touching the spring of the air, and its effects, made, 

 for the most part, in a new pneumatical engine. Oxford : VV. 

 Hall, 1660. 



29. Mayow, John (1645-1679). Tractus Duo, quorum prior 

 agit De Respiratione : alter De Radutiones. O.xford: Hall, 1668. 



30. Willis, Thomas (1621-1675). Cerebri anatome: cui accessit 

 nervorum descriptio et usus. (Z)f systemate nervosa in genere"), 

 illustrated by Sir Christopher Wren. London: Flesher, 

 1664; translated into English by S. Pordage. London: 

 Dring, Harper and Leigh, 1683. 



' Letter to Mersenne dated 1632, quoted in Oeuvres Com- 

 pletes de Descartes, edition of Adam and Tannery, Paris; Cerf, 



1897-1910, vol. n, p. 127. 



