CHAPTER I 



The historical development of neurophysiology 



MARY A. B. BRAZIER \ Ma'^sachusetts General Hospital, Boston, Massachusetts 



CHAPTER CONTENTS 



Early Concepts of Nervous Activity 



ENcitability anci Transmission in Nerves 



Spinal Cord and Reflex Activity 



Physiology of the Brain: Development of Ideas and Growth of 



Experiment 

 Short List of Secondary Sources 

 Biographies 



EARLY CONCEPTS OF NERVOUS ACTIVITY 



IN CONTRAST TO MEDICINE, a sciencc demanding 

 synthesis of observations, experimental physiology, 

 with its reliance on analysis and laboratory work, has 

 little significant history before 1600. Leaders in 

 medicine developed and practiced its therapies for 

 many centuries before they felt the need to under- 

 stand the nature and functions of the body's parts in 

 any truly physiological sense and, when the urge for 

 this knowledge first arose, it was to come as mucli 

 from the philosophers as from the healers of the sick. 

 Neurophysiology (a term not to come into use 

 until centuries later) had as a legacy from the ancients 

 only their speculative inferences and their primitive 

 neuroanatomy. Aristotle had confounded nerves 

 with tendons and ligaments, had thought the brain 

 bloodless and the heart supreme, not only as a source 

 of the nerves but as the seat of the soul. Herophilos 

 and Erisistratos had recognized the brain as the 

 center of the nervous svstem and the nerves as con- 

 cerned both with sen.sation and movement. However, 

 preliminary to all disciplines was the development of 

 the scientific method and in this Aristotle was a fore- 

 runner. If Aristotle is to be evaluated as a scientist, it 

 must be admitted that he was almost always wrong in 



every inference he made from his \ast collections of 

 natural history and numerous dis.sections; yet in spite 

 of the stultifying effect of the ininujdcrate worship 

 gi\en him by generations to follow, he stands out as a 

 pioneer in the background of every scientific dis- 

 cipline. He owes this position to his in\ention of a 

 formal logic, and although his system lacked what the 

 modern scientist uses most, namely hypothesis and 

 induction, his was a first step towards the introduc- 

 tion of logic as a tool for the scientist. Unfortunately 

 Aristotle did not use his logic for this purpose him- 

 .self ' As Francis Bacon put it, Aristotle "did not con- 

 sult experience in order to make right propositions 

 and axioms, but when he had settled his system to 

 his will, he twisted experience round, and made her 

 bend to his system." 



In the .second century A.D., Galen's experimental 

 work added little to establish the functions of the 

 animal structures he dissected, though the hypotheses 

 he suggested were put forward so authoritatively 

 that they remained unchallenged for nearly 1500 

 years. To the intervening centuries, dominated as 

 they were by the Christian church, the teleology 

 implicit in Galen's approach was attractive. Early 

 Western acquaintance with his writings depended 

 entirely upon Latin translations of Arabic. It was only 

 after the fall of the Byzantine Empire and the expul- 

 sion of the Greek monks from the area of Turkish 

 concjuest that the Greek language began to be read at 



' The fragments of Aristotle's writings that e.xist (probably 

 his lecture notes} were not collected until more than lioo 

 years after his death. His Opera were among the early scientific 

 works to be printed (in Latin, 1472), nearly 1800 years after his 

 death. English translations (The Works of Aristotle) were pub- 

 lished by the Clarendon Press, Oxford, in several volumes 

 between 1909 and 1931, edited by J. A. Smith and W. A. Ross. 



